Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis

Revision surgery for proximal junctional failure: A single-center analysis

BACKGROUND

Proximal junctional kyphosis (PJK) is a radiographic complication following adult spinal deformity (ASD) surgery due to degeneration of mobile segments adjacent to fused spine. Proximal junctional failure (PJF) represents PJK with structural failure, neurologic deficit, or mechanical instability warranting revision with extension of fusion above the uppermost instrumented vertebra (UIV). This study investigates the clinical presentation, mechanisms of failure, revision strategies, and outcomes for ASD patients who develop PJF after instrumented fusion to the pelvis.

METHODS

Fifty-four ASD patients who developed PJF after a posterior instrumented fusion to the pelvis at a single institution from 2009 to 2021 were analyzed. PJF was defined by radiographic PJK with (1) UIV or UIV+1 fracture, UIV screw pullout, or soft-tissue posterior ligamentous disruption, and (2) neurological deficit at presentation.

RESULTS

The cohort was stratified into upper thoracic (UT, 10 patients, T2-T6), lower thoracic (LT, 35 patients, T8-T11), and lumbar (L, 9 patients, L1-L3) spine UIV groups based on index surgery. Patients developed PJF at a median of 14 months (mean 18 ± 16, range: 1-78) after their index surgery. Neurological deficits at presentation included radiculopathy (61 %), myelopathy (48 %), motor deficits (33 %), and bowel or bladder incontinence (9 %). Mechanisms of PJF were vertebral fracture and screw pullout (UT: 50 %, LT: 80 %, L: 89 %, P < 0.001) or soft-tissue disruption (UT: 50 %, LT: 20 %, L: 11 %, P = 0.089) at the UIV. Revision surgery commonly involved posterior column osteotomies (63 %) rather than three-column osteotomies (9 %). Of patients in the UT group, 40 % were extended above the cervicothoracic junction. In the LT and L groups, 91 % and 89 % of patients were extended to the UT and LT spine, respectively. Median follow-up for the cohort after revision for PJF was 24 months (range: 2-89). A total of 26 patients (48 %) required a second revision surgery (median 14 months, range: 1-50), 16 of whom (28 %) were revised for recurrent PJF. Patient-specific and radiographic risk factors for recurrent PJF could not be elucidated.

CONCLUSION

In this series of ASD patients, after revision for PJF, recurrent PJF was the most common complication requiring another revision. Junctional failures tended to be vertebral body fracture and screw pullout in the LT and L spine and soft tissue disruption in the UT spine. Most revisions involved posterior column osteotomies with proximal extension across the thoracolumbar junction or apex of thoracic kyphosis (e.g., L to LT, LT to UT); notably, nearly half of UT failures were not extended to the cervical spine. Future research is warranted to elucidate risk factors for recurrent PJF and potential preventative strategies.

Who benefits from home-based exercise for adult spinal deformity? A prospective multicenter study on clinical and radiographic predictors

PURPOSE

The prevalence of adult spinal deformity (ASD) is expected to exceed 60 million by 2050 due to an aging population and increased life expectancy. Despite advances in surgery, high complication rates and the economic burden highlight the need for effective non-surgical treatments. This study assesses the "Koshimagari Exercise," a self-exercise program for ASD patients, and aims to develop a classification system to identify those who would benefit most.

METHODS

A prospective cohort study was conducted across 13 facilities, enrolling 144 participants from December 2020 to June 2022. The inclusion criteria were adults aged 50-80 years with chronic low back pain due to spinal deformities. Participants attended weekly physiotherapist-led exercise sessions and performed self-exercises at home three times a week, focusing on flexibility, functional improvement, trunk and back muscle strengthening, motor learning, and pain control. The primary outcome was the change in the Oswestry Disability Index (ODI) from baseline to 6 months post-intervention, with a 12-month follow-up. Clinical evaluations included health-related quality of life (HRQOL) assessments with ODI and EuroQol-5 Dimensions (EQ-5D), spinal alignment radiography, and magnetic resonance imaging of the paravertebral muscle (PVM) cross-sectional area.

RESULTS

Of the 130 participants who provided written informed consent, 98 completed the 6-month follow-up. The study found that 42% of patients achieved a minimum clinically important difference (MCID) in ODI, with significant improvements in EQ-5D scores and LBP from baseline. Patients who achieved MCID had lower baseline body mass index and EQ-5D scores, and higher baseline ODI scores compared to those who did not. Logistic regression identified three significant predictors of MCID achievement: L4/S1 angle, the difference between standing and supine thoracolumbar kyphosis (ΔTLK), and the relative cross-sectional area (rCSA) of the PVM at L4/5. Based on these findings, a classification system was developed, dividing patients into Self-Exercise-Friendly and Self-Exercise-Limited groups, with a significant difference in ODI improvement observed between these groups at 6 months post-intervention.

CONCLUSION

The "Koshimagari Exercise," a novel self-exercise program for ASD, achieved an MCID in the ODI for 42% of patients. The classification system, incorporating L4/S1 angle, ΔTLK, and L4/5 rCSA, is associated with improvements in HRQOL and may help identify patients who are more likely to benefit from this home-based exercise program.

Comparing Spinopelvic Angles and Magnification on Supine MRI With Standing Radiographs in Lumbar Spinal Stenosis

STUDY DESIGN

Radiologic cross-sectional study based on a prospective cohort study (level III).

OBJECTIVE

Investigate whether lumbar lordosis (LL) and sacral slope (SS) differ significantly on supine magnetic resonance imaging (MRI) versus standing radiographs in nondeformity lumbar spinal stenosis (LSS). Secondly, to quantify the amount of magnification on standing lumbar radiographs.

SUMMARY OF BACKGROUND DATA

Supine MRI is routinely performed when diagnosing LSS. Standing radiographs are often supplemented to measure spinopelvic angles. Little research has been done on whether LL and SS translate from standing radiographs to supine MRI. Previous studies have trended to significant changes in LL and SS; however, none have been performed exclusively in nondeformity LSS.

MATERIALS AND METHODS

Review of preoperative standing lateral lumbar radiographs and midsagittal T2-weighted supine lumbar MRI in 211 patients with LSS without concomitant degenerative spondylolisthesis, measuring LL (L1-S1), segmental lumbar lordosis (sLL) (L4-S1) and SS, in addition to the anteroposterior diameter and height of the L3 vertebral body. We conducted a reliability study and performed a Pearson's correlation analysis. Data was presented in Bland-Altman plots.

RESULTS

Interobserver reliability was good to excellent, with ICC ranging from 0.77 to 0.94 for all parameters. Statistically significant differences were observed in LL and SS between image modalities. The mean radiographic measurements were as follows: LL 48.9 (SD: 12.8), sLL 32.3 (SD: 8.1), and SS 37.3 (SD: 8.7) degrees. The mean MRI measurements were as follows: LL 46.0 (SD: 10.5), sLL 32.3 (SD: 7.1), and SS 38.1 (SD: 7.1) degrees. Mean vertebral body magnification was between 21% and 23% for L3 anteroposterior diameter and height.

CONCLUSIONS

Our results suggest that supine lumbar MRI might be a viable alternative to standing lateral lumbar radiographs for measuring LL and SS in routine follow-up for patients with LSS without concomitant spinal deformity. Standing radiographs are recommended as part of the initial investigation for LSS. Standing lumbar radiographs may yield high grades of magnification.

Sarcopenia Predicts Early Adjacent Segment Disease Development After Anterior and Oblique Lumbar Interbody Fusion

BACKGROUND AND OBJECTIVES

Sarcopenia has recently been shown to increase risk of early adjacent segment disease (ASD) development after transforaminal lumbar interbody fusion. We sought to evaluate whether sarcopenia increases risk of ASD after retroperitoneal approaches for lumbar interbody fusion (eg, anterior lumbar interbody fusion or oblique lateral lumbar interbody fusion).

METHODS

Retrospective data were collected from 104 adult patients aged older than 18 years who underwent short-segment fusion through anterior lumbar interbody fusion or oblique lateral lumbar interbody fusion approach from 2013 to 2023. The primary outcome was development of ASD within 3 years of surgery. Patients who had prior surgery for ASD, underwent long-construct deformity correction, had an ongoing oncological process, or lacked sufficient follow-up were excluded. Psoas and vertebral body volumetric measurements were calculated at the L4 pedicle level using preoperative MRI. Spinopelvic parameters of pelvic tilt, pelvic incidence (PI), lumbar lordosis (LL), and PI-LL mismatch were recorded from standing upright radiographs. Odds ratios were calculated with logistic regression analyses.

RESULTS

Of 104 patients undergoing fusion through retroperitoneal approaches, 25 (24.04%) developed ASD within 3 years. Patient demographics and medical comorbidities did not predict early ASD. Left and right psoas area (cm2) and psoas:vertebral body ratio strongly predicted ASD development (P < .0001). Nineteen patients were categorized as sarcopenic, defined as bilateral psoas:vertebral body ratios >1 SD below the study population gender mean. 16 of the 19 sarcopenic patients developed ASD within 3 years, compared with 9 of the 85 nonsarcopenic patients (84.21% vs 10.59%, P < .0001). Postoperative pelvic tilt and PI-LL mismatch were predictive of ASD on univariate but not multivariate analysis.

CONCLUSION

Sarcopenia significantly predicts ASD development within 3 years after lumbar fusion through retroperitoneal approaches. Irrespective of approach, sarcopenia is a risk factor of ASD formation and should be evaluated preoperatively. Morphometric analysis provides a simple screening tool and can be used to tailor preoperative and postoperative therapies to improve outcomes.

Frequency of lumbopelvic malalignment in symptomatic hip instability and impingement - a prospective, diagnostic cohort study

INTRODUCTION

The dynamic lumbopelvic interaction has gained increasing importance in hip-preserving surgery, even though the coexistence of lumbopelvic malalignment with pre-arthritic hip deformities has been poorly studied. This study aimed to examine (I) the frequency of static and functional lumbopelvic malalignment (II) and to compare the lumbopelvic alignment between symptomatic mild to severe hip dysplasia (HD) and impingement-driven acetabular retroversion (AR).

METHODS

Sagittal lumbopelvic radiographs were reviewed in standing, relaxed-seated and deep-seated position for pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), and sacral slope (SS). Static lumbopelvic alignment was classified as "Flatback", "Normal", or "Hyperlordotic" and functional lumbopelvic alignment was categorized as "Stiff", "Normal", and "Hypermobile". Static and functional (Δ between the above-mentioned positions) lumbopelvic parameters were compared among HD, borderline hip dysplasia (BHD), and AR.

RESULTS

Ninety-eight patients undergoing hip-preserving surgery for HD (n = 47), BHD (n = 36), and AR (n = 15) were prospectively enrolled. Static lumbopelvic malalignment occurred in 44.9% of patients (44/98), with "Hyperlordotic" alignment being the most frequent (36/44). Additionally, 28.6% of patients (28/98) exhibited functional lumbopelvic malalignment. Static lumbopelvic parameters showed differences between hip instability and impingement, with lower PI (42° vs. 57.3°, p = 0.001; 42° vs. 53.7°, p = 0.01) and PT (5.6° vs. 15.8°, p < 0.001; 5.6° vs. 12.4°, p = 0.01) in AR patients compared to HD and BHD in standing position. Moreover, SS was significantly lower in AR (40.9° vs. 50.1°, p = 0.02) and BHD (43.8° vs. 50.1°, p = 0.05) compared to HD in deep-seated position. Significant differences in functional lumbopelvic parameters were observed only between HD and BHD in PT (Δ standing - deep-seated position, 7.1° vs. -1.2°, p = 0.04).

CONCLUSION

Static and functional lumbopelvic malalignment is prevalent in patients with pre-arthritic hip deformities. While static lumbopelvic parameters vary between instability- and impingement-driven hip deformities, functional lumbopelvic alignment is quite similar among HD, BHD, and AR.

Utility of the psychache scale in patients undergoing surgery for degenerative lumbar disease: a prospective single-center study

PURPOSE

This study aims to psychometrically validate the Psychache Scale (PAS) and investigate its prognostic value in predicting postoperative outcomes.

METHODS

This is a prospective single-center study. Adults undergoing lumbar or thoracolumbar surgery were recruited. Participants completed PAS preoperatively and patient-reported outcome measures evaluating mental health, pain, physical function, and disability preoperatively and at one and six months postoperatively. PAS internal consistency was evaluated by Cronbach's alpha coefficient, and factor structure was evaluated using confirmatory factor analysis. Construct validity was assessed by examining correlations between PAS and measures of mental and physical health. PAS prognostic utility was evaluated by assessing its association with short- and longer-term surgical outcomes.

RESULTS

We included 166 patients. Mean (SD) age was 59.7 (12) years, with 55% females. PAS reliability was high (Cronbach's alpha = 0.95), and factor analysis confirmed the hypothesized one-factor structure. PAS showed strong correlations with PHQ-9 (r = 0.64), PROMIS anxiety (r = 0.64), pain catastrophizing scale (PCS) (r = 0.7), and its helplessness (r = 0.72), magnification (r = 0.59), and rumination (r = 0.59) subscales. However, it shows weak to moderate correlations with non-mental health-related metrics (0.07 < r < 0.44). Preoperative PAS was moderately correlated with one-month pain interference, and six-month PHQ-9 and PROMIS anxiety scores. In predicting outcomes, the addition of PAS to models including baseline values improved the prediction of all outcomes except for PROMIS physical function.

CONCLUSIONS

Our study suggests PAS may be a valuable tool for assessing psychological distress in this patient population. Further research is needed to understand its relevance in spine surgery practice.

LEVEL OF EVIDENCE

II.

Impact of spinal alignment on adjacent segment disease and degeneration after short-segment lumbosacral fusion

BACKGROUND CONTEXT

Adjacent segment disease (ASDis) and degeneration (ASDeg) are common complications following lumbar fusion, ranging from asymptomatic radiographic changes to debilitating symptoms requiring revision surgery. While the impact of spinopelvic alignment (SPA) on postoperative outcomes and ASDis prevention is well-studied in long-construct fusions, its role in short-segment lumbosacral fusions, particularly over the long term, remains unclear.

OBJECTIVE

This study aimed to investigate the association between global and distal lumbar SPA with the development of ASDis and ASDeg in the long-term follow-up of patients undergoing short-segment lumbosacral fusion. Secondary outcomes were patient reported outcome measures (PROMs) in relation to adjacent segment changes.

STUDY DESIGN/SETTING

Retrospective single-center cohort study with minimum follow-up of 5 years.

PATIENT SAMPLE

A total of 86 patients who underwent L4-S1 spinal fusion between 2003 and 2015, with a mean follow-up of 12±4 years.

OUTCOME MEASURES

The primary outcome was the development of adjacent segment changes, classified into 2 groups: (1) surgically-treated ASDis, and (2) ASDeg, defined as radiographic evidence of adjacent segment changes without surgical intervention. Secondary outcomes included PROMs: the Oswestry Disability Index (ODI) and the European Quality of Life 5 Dimensions 5 Level (EQ5D5L).

METHODS

Pre- and postoperative standing radiographs were annotated and the following global lumbar SPA parameters analyzed: Pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), PI-LL-mismatch, lumbar pelvic angle (LPA). Additionally, the following distal lumbar SPA parameters were analyzed: Distal lordosis (DL) between L4-S1, lordosis distribution index (LDI=DL/LL), PI-DL-difference, DL-PI-ratio, adjacent segment lordosis (ASL). Postoperative ODI and EQ5D5L were assessed via a telephone interview.

RESULTS

Among 86 patients with a mean follow-up of 12±4 years the incidence of ASDis was 27.9% (n=24), while 7.0% (n=6) showed ASDeg. No significant differences in pre- and postoperative global lumbar SPA were found in patients who developed ASDis or ASDeg compared to patients who did not. PI (53.6° vs. 59.6°) and preoperative SS (34.9° vs. 40.3°) trended to be lower in the ASDis group compared to controls, although non-significant. Pre- and postoperative distal lumbar SPA parameters did not differ between groups. Patients with adjacent segment changes, regardless of whether they underwent revision surgery, reported worse PROMs. ODI scores were elevated in both the ASDis group (28, IQR 15-42) and the ASDeg group (34, IQR 14-47) compared to controls (10, IQR 2-24; p=.005). EQ5D5L scores were lower in both the ASDis (70, IQR 53-83) and the ASDeg groups (60, IQR 55-85) compared to controls (85, IQR 75-90; p=.025).

CONCLUSION

In this long-term follow-up study of patients undergoing short-segment lumbosacral fusion, neither preoperative nor postoperative SPA was significantly associated with the development of ASDis or ASDeg. These findings suggest that other factors may have a greater influence on ASDis risk. Patients who developed adjacent segment changes, whether or not they required revision surgery, experienced worse long-term postoperative PROMs, indicating the importance of ASDis prevention.

Lumbopelvic hyperlordosis is linked to higher femoral head coverage, lower femoral anteversion and younger age at periacetabular osteotomy

PURPOSE

The dynamic alignment of the lumbar spine, pelvis and femur is increasingly studied in hip preservation surgery. However, the interaction between lumbopelvic alignment, acetabular and femoral morphology and its influence on patients' preoperative symptom burden remains poorly understood. The aim of this study was to evaluate whether lumbopelvic malalignment affects osseous hip morphology and exacerbates preoperative patient-reported joint functionality in patients undergoing periacetabular osteotomy (PAO).

METHODS

One hundred thirteen patients were prospectively enroled in this single-centre study. Sagittal lumbopelvic radiographs were used to divide the patients in accordance with their lumbopelvic alignment (pelvic incidence [PI]-lumbar lordosis [LL] mismatch) into a balanced (PI-LL: 10° and 10°/n = 60) and unbalanced alignment (PI-LL: <10° and >10°/n = 53) group. Intergroup analyses were performed for acetabular and femoral morphology as well as various patient-reported outcome measures (PROMs) scores (modified Harris-Hip, Hip Osteoarthritis Outcome, International Hip Outcome tool-12 and University of California Los Angeles activity scale).

RESULTS

Patients with concomitant unbalanced lumbopelvic alignment due to hyperlordosis showed higher femoral head coverage and lower femoral anteversion (lateral centre-edge angle 20.2° vs. 15.8°, p = 0.012/anterior wall index 0.47 vs. 0.36, p = 0.001/acetabular inclination 10.2° vs. 13.6°, p = 0.008/Femoral anteversion 21.3° vs. 28.2°, p = 0.041). Furthermore, these patients were significantly younger at the time of PAO (28.7 vs. 32.4 years, p = 0.020), even when there were no intergroup differences in all analyzed PROMs.

CONCLUSION

Concomitant lumbopelvic deformity affecting the hip joint morphology could aggravate clinical symptoms leading to earlier presentation in patients undergoing PAO. Thus, the lumbopelvic balance needs to be carefully evaluated in clinical decision-making in PAO patients and future research should focus on long-term outcomes of patients with concomitant unbalanced lumbopelvic alignment.

LEVEL OF EVIDENCE

Level III, prognostic study.

Coronal Deformity is Associated With Uptake on Single Photon Emission Computed Tomography in Patients With Low Back Pain

Study DesignRetrospective Cohort Study.ObjectiveSingle Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) is emerging as a valuable imaging test for identifying pain generators within the lumbar spine. The relationship between radiotracer uptake on SPECT/CT and anatomic biomechanical parameters has not been previously studied.MethodsWe performed a retrospective review of all patients seen at our institution between 2021-2023 who obtained SPECT/CT scans for workup of thoracolumbar back pain. Patient data including demographic, clinical symptoms, and surgical history were collected. Radiology reports were reviewed for evidence of pathologic degeneration and increased bone metabolism on SPECT/CT. Biomechanical parameters were measured from standing scoliosis plain radiographs. Patients were stratified into two cohorts by either presence or absence of asymmetric coronal uptake on SPECT/CT.Results160 patients met inclusion criteria. Patients were primarily male (55%) with average age 55 ± 15 years. 87 (54%) patients demonstrated asymmetric uptake on SPECT/CT. These patients were older (P < 0.001), but with similar gender, prior fusion history, sacroiliitis, adjacent segment degeneration, and pseudoarthrosis (P > 0.05). This cohort had more disc disease, facet arthropathy, and greater degree of coronal scoliosis and coronal imbalance (P < 0.001). There were significantly more sites of uptake in the asymmetric cohort, and uptake was preferentially observed in the concavity of the lumbar curve (P < 0.001). There were no significant differences in sagittal balance or spinopelvic mismatch between cohorts (P > 0.05).ConclusionAsymmetric uptake on SPECT/CT was associated with coronal deformity in patients with low back pain. Further prospective studies are warranted to assess the effect of coronal deformity on pain generation.

Posterolateral Fusion Versus Posterior Lumbar Interbody Fusion for Adult Low-Grade Isthmic Spondylolisthesis: Analysis of Sagittal Radiographic Parameters - A Randomized Controlled Trial

Study DesignRandomized controlled trial.ObjectivesTo compare the effect of posterolateral fusion (PLF) and posterior lumbar interbody fusion (PLIF) on sagittal radiographic parameters in patients with low-grade isthmic spondylolisthesis. Additionally, to explore the correlation between changes in these parameters and clinical outcomes.MethodsForty-six consecutive patients with single-level low-grade isthmic spondylolisthesis were initially enrolled. They were randomly assigned to undergo either PLF or PLIF. Patients were followed up for at least 24 months. Radiographic outcomes included pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, sagittal vertical axis, T1 pelvic angle, slip angle, slip degree and disc height. Clinical outcomes were assessed by the Oswestry Disability Index (ODI) and visual analogue scale (VAS).ResultsFour participants were lost to follow-up. Of the remaining 42 patients, 29 were female. The mean age was 40.23 ± 10.25 years in the PLF group and 35.81 ± 10.58 years in the PLIF group. There was a statistically significant greater correction of all radiographic parameters in the PLIF group. The ODI and VAS improved significantly in both groups, with no significant differences between the two groups. Changes in the ODI and VAS were significantly correlated with changes in disc height, slip angle and lumbar lordosis.ConclusionsIn patients with low-grade isthmic spondylolisthesis, PLIF demonstrates superior efficacy compared to PLF in correcting sagittal radiographic parameters. Nevertheless, this distinction does not seem to influence short-term clinical results. Restoring disc height, correcting the slip angle, and reestablishing normal lumbar lordosis are crucial steps in the surgical management of isthmic spondylolisthesis.

Does the Lumbar Paraspinal Muscle Status Have a Role in Predicting Mechanical Complications After Adult Spinal Deformity Surgery?

Study designRetrospective analysis.ObjectivesTo assess the role of paraspinal muscle morphology in predicting complications after adult spinal deformity (ASD) surgery.Materials and MethodsA total of 93 patients who underwent surgery for ASD from 2017 to 2022 were enrolled. Using early postoperative X-ray, they were divided into proportioned (P), moderately proportioned (MP), and severely proportioned (DP) groups based on the Global Alignment and Proportion (GAP) scores. Further, they were classified into two groups: Group A (presence of mechanical complications) and Group B (no mechanical complications). In addition, other parameters including preoperative BMI, smoking status, cross-sectional area (CSA), and grades of paraspinal muscle fatty infiltration (FI) were calculated in all patients using preoperative MRI. These parameters were compared across the groups using a one-way analysis of variance (ANOVA). Post-hoc pairwise testing was done using Bonferroni's method. These were also compared between groups A and B using a 2-sample t-test.ResultsThe mean follow-up period was 32.7 months (24-64 months). 27 (29%) of 93 patients developed mechanical complications following ASD surgery. Of the 27 patients, 6 (22.2%) were proportioned, 10 (37%) were from MP and 11 (40.7%) were from the DP group. Group A had low CSA (P = 0.014), and high FI (P = 0.003) grades compared to group B. Further, 22.2% (6/27) had a history of smoking before surgery (OR = 6.57).ConclusionsWe recommend consideration of preoperative smoking, CSA, and FI of paraspinal muscles in addition to the GAP score to minimize mechanical complications in patients undergoing ASD surgery.

How to Reduce the Risk of Mechanical Failures in Adult Deformity Surgery: Comparing GAP Score and Roussouly Type Restoration

Study DesignRetrospective Cohort Study.ObjectivesTo assess long-term alignment descriptors correlating with mechanical complications.MethodsThe study included adult spinal deformity cases older than 18, with a minimum of four instrumented levels and a 5-year follow-up. Exclusions: previous spinal fusion, neuromuscular/rheumatic diseases, active infections, tumors, or incomplete radiographic exams. Collected data: demographic, surgical, pre- and post-operative spinopelvic parameters, and post-operative complications. The GAP score, original Roussouly type restoration, Schwab's criteria, and Odontoid to hip axis angle were evaluated using machine learning and logistic regression. Complications were evaluated with a Kaplan-Meier curve.ResultsTwo hundred and twelve patients fulfilled the inclusion and exclusion criteria and were enrolled in the study. The observed rate of revision surgery for mechanical complications was 40.6% (86 out of 212 patients). Higher post-operative GAP scores were associated with increased risks of revision for junctional failure (AUC = 0.72 [IC 95%] 0.62-0.80). The inability to restore the original Roussouly spinal shape was statistically associated with higher mechanical failure rates. A machine-learning approach and subsequent logistic regression found that the GAP score and original Roussouly type restoration are the most important predictors for mechanical failure, and GAP score lordosis distribution index and relative pelvic version are the most important factors to predict the risk of mechanical failure.ConclusionsIn our series, a proper post-operative GAP Score and the restoration of the original Roussouly type significantly minimize mechanical complication rates. We observed that junctional failure tends to occur earlier among complications, while implant failure occurs later in the follow-up.

The relationship between spinopelvic alignment and knee osteoarthritis in female patients: A cross-sectional study

BackgroundThe spine, pelvis, and lower extremities move in the form of a kinematic chain.ObjectiveThis study aimed to evaluate the relationship between spinopelvic parameters and knee osteoarthritis.MethodsSixty-nine participants (50-70 years) were diagnosed with knee osteoarthritis: early-stage (n = 36) and late-stage (n = 33). Knee osteoarthritis severity was assessed using standing antero-posterior radiographs (Kellgren-Lawrence scores). A visual Analog Scale was used to evaluate knee and lumbar pain, the Western Ontario and McMaster Universities Osteoarthritis Index to evaluate knee joint function and disability, and the Oswestry Low Back Pain Disability Index to evaluate disability associated with lumbar pain. Lateral scoliosis radiographs were taken of all the study participants; pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis, and sagittal vertical axis values were measured and recorded.ResultsMultivariate logistic regression analysis was performed to determine the independent risk factors associated with the clinical and radiological osteoarthritis severity as Body Mass Index, sagittal vertical axis and lumbopelvic mismatch increased. The sacral slope values were determined to be independently negatively correlated with the clinical osteoarthritis severity. However, no correlation was determined with the radiological severity.ConclusionIn this study, we determined that global sagittal imbalance and lumbopelvic mismatch are associated with advanced knee osteoarthritis. Although pelvic retroversion was not found to be correlated with the radiographic severity of osteoarthritis, it was found to be associated with poor functional results.

Association Between Spinopelvic Alignment and Reoperation Following Percutaneous Transforaminal Endoscopic Decompression: A Matched Case-Control Study

Purpose

Percutaneous transforaminal endoscopic decompression (PTED) is widely used for treating lumbar spinal stenosis (LSS), yet predictors of reoperation remain unclear. This study aimed to explore the association between spinopelvic alignment and the reoperation following PTED.

Patients and Methods

A 1:2 matched case-control study was conducted, involving patients who underwent single-level PTED for LSS at our institution from May 2014 to August 2022. Cases comprised patients requiring reoperation after initial PTED, while controls were those without reoperation during the follow-up. Measured radiological parameters included pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), mismatch between pelvic incidence and lumbar lordosis (PI-LL), disc height (DH), Pfirrmann classification, and Modic changes (MCs). Univariate and multivariate logistic regression analyses were performed to identify predictors. Receiver operating characteristic (ROC) curves were generated to determine cut-off points.

Results

76 cases and 152 controls were selected from 1967 enrolled patients. Both groups had an average age of 61 years, a male-to-female ratio of 43:33, and a mean BMI of 25.95 kg/m². No significant differences in baseline characteristics were found between groups. Multivariate analysis identified PT (OR = 1.061, P = 0.007), PI-LL (OR = 1.057, P = 0.021), and DH (OR = 1.194, P = 0.015) as independent risk factors for the reoperation. ROC analysis revealed PI-LL with an area under the curve (AUC) of 0.662 at a cut-off of 12.95° (95% CI = 0.582-0.741), PT with an AUC of 0.685 at a cut-off of 21.98° (95% CI = 0.606-0.763), and DH with an AUC of 0.602 at a cut-off of 8.22° (95% CI = 0.521-0.683).

Conclusion

PI-LL ≥ 12.95°, PT ≥ 21.98°, and DH ≥ 8.22° are independent risk factors for reoperation following PTED.

Characteristics of Spinal Morphology According to the "Current" and "Theoretical" Roussouly Classification Systems in a Diverse, Asymptomatic Cohort: Multi-Ethnic Alignment Normative Study (MEANS)

STUDY DESIGN

Cross-sectional cohort study.

OBJECTIVE

To classify spinal morphology using the "current" and "theoretical" Roussouly systems and assess sagittal alignment in an asymptomatic cohort.

METHODS

467 asymptomatic volunteers were recruited from 5 countries. Radiographic parameters were measured via the EOS imaging system. "Current" and "theoretical" Roussouly classification was assigned with sagittal whole spine imaging using sacral slope (SS), pelvic incidence (PI), and the lumbar apex. One-way analysis of variance (ANOVA) was performed to compare subject characteristics across Roussouly types, followed by post hoc Bonferroni correction.

RESULTS

Volunteers were categorized into 4 groups (Types 1-4) and 1 subgroup (Type 3 AP) using the "current" and "theoretical" Roussouly systems. The mean PI in "current" Roussouly groups was 40.8° (Type 1), 43.6° (Type 2), 52.4° (Type 3), 62.4° (Type 4), and 43.7° (Type 3AP). The mean PI in "theoretical" Roussouly groups was 36.5° (Type 1), 39.1°(Type 2), 52.5° (Type 3), 67.3° (Type 4), and 51.0° (Type 3AP). The difference in PI between "current" and "theoretical" Roussouly types was significant for Type 1 (P = .02), Type 2 (P < .001), Type 4 (P < .001), and Type 3AP (P < .001). 34.7% of subjects had a "current" Roussouly type different from the "theoretical" type. Type 3 theoretical shape had the most frequent mismatch, constituting 61.1% of the mismatched subjects. 51.5% of mismatched Type 3 become "current" Type 4.

CONCLUSION

The distribution of Roussouly types differs depending on whether the "current" or "theoretical" classification are employed. A sizeable proportion of volunteers exhibited current and theoretical type mismatch, highlighting the need to interpret sagittal alignment cautiously when utilizing the Roussouly system.

Is Age a Risk Factor for Early Postoperative Cage Subsidence After Transforaminal Lumbar Interbody Fusion? A Retrospective Study in 170 Patients

STUDY DESIGN

Retrospective observational study.

OBJECTIVES

We aim to evaluate whether age is a risk factor for cage subsidence, and whether other patient characteristics, preoperative radiological or imaging parameters are associated with cage subsidence and the need for revision surgery in patients undergoing transforaminal lumbar interbody fusion (TLIF).

METHODS

Patient demographics and surgery-related information were extracted. Cage subsidence was evaluated using upright standing sagittal plane X-rays and defined as more than 2 mm migration of the cage into the adjacent vertebral body. Patients who received revision surgery within 1 year for any reason were recorded. Radiographic parameters were measured. Univariable logistic regression models were used to evaluate the risk factors for cage subsidence and need for revision surgery.

RESULTS

At 3-month and 1-year follow-up, cage subsidence was observed in 28 patients (16.5%) and 58 patients (34.1%), respectively. Twenty-seven patients received revision surgery within the first year after TLIF. Age (odds ratio (OR): 1.07 per year) and male sex (OR: 2.76) had a significantly increased odds ratio for cage subsidence 3 months after TLIF. Male sex (OR: 2.55) but not age was a significant risk factor for cage subsidence 1 year after TLIF. Of all assessed risk factors, only BMI (OR: 1.11 per kg/m2) had a significantly increased risk for the need of revision surgery.

CONCLUSIONS

Age was associated with cage subsidence 3 months but not 1 year after TLIF suggesting that age is only a risk factor for early cage subsidence and not in a longer follow-up.

The lower Osteotomy Level is Associated With Decreased Revision Surgery Due to Mechanical Complications After Three-Column Osteotomy in Patients With Adult Spinal Deformity: A Multi-Institutional Retrospective Study

STUDY DESIGN

A multi-institutional retrospective study.

OBJECTIVES

To investigate risk factors of mechanical failure in three-column osteotomy (3COs) in patients with adult spinal deformity (ASD), focusing on the osteotomy level.

METHODS

We retrospectively reviewed 111 patients with ASD who underwent 3COs with at least 2 years of follow-up. Radiographic parameters, clinical data on early and late postoperative complications were collected. Surgical outcomes were compared between the low-level osteotomy group and the high-level osteotomy group: osteotomy level of L3 or lower group (LO group, n = 60) and osteotomy of L2 or higher group (HO group, n = 51).

RESULTS

Of the 111 patients, 25 needed revision surgery for mechanical complication (mechanical failure). A lower t-score (odds ratio [OR] .39 P = .002) and being in the HO group (OR 4.54, P = .03) were independently associated with mechanical failure. In the analysis divided by the osteotomy level (LO and HO), no difference in early complications or neurological complications was found between the two groups. The rates of overall mechanical complications, rod failure, and mechanical failure were significantly higher in the HO group than in the LO group. After propensity score matching, mechanical complications and failures were still significantly more observed in the HO group than in the LO group (P = .01 and .029, respectively).

CONCLUSIONS

A lower t-score and osteotomy of L2 or higher were associated with increased risks of mechanical failure. Lower osteotomy was associated with better correction of sagittal balance and a lower rate of mechanical complications.

Effect of sagittal spinal alignment on knee pain in patients with severe knee osteoarthritis: A cross-sectional study

BACKGROUND

Sagittal spinal alignment is closely related to knee joint function, and sagittal malalignment can affect knee joint pain. This study investigated the association between knee joint pain intensity and sagittal spinal alignment in patients with knee osteoarthritis.

METHODS

This retrospective study enrolled 187 patients with knee osteoarthritis who were scheduled for primary unilateral total knee arthroplasty (TKA) from December 2021 to March 2023. Patients were assigned to either the Normal or Imbalance group according to the pelvic incidence (PI) minus lumbar lordosis (LL) values. Knee joint function was compared between patients with and without matched sagittal spinal alignment. The primary outcome was patient-reported pain intensity.

RESULTS

A total of 132 patients (22 men and 110 women, mean age: 75 ± 6.7 years [range, 55-89 years], mean body mass index: 25.3 ± 3.8 kg/m²) were evaluated preoperatively. The Imbalance group categorized by PI minus LL values (≥10) comprised 45 patients (34 %, mean age: 76.5 ± 5.9 years, mean body mass index: 25.5 ± 3.3 kg/m²). The mean pain intensity on the affected side was significantly higher in the Imbalance group (P = 0.020). No differences in psychosocial factors were found between the two groups. Knee joint function regarding knee joint extension angle in the standing position was significantly greater in the Imbalance group (P = 0.035).

CONCLUSION

Sagittal plane malalignment was associated with knee joint pain in patients with knee osteoarthritis who were scheduled for TKA. Our results suggest the need for preoperative pain control interventions that consider the effects of sagittal spinal alignment.

Analysis of Personalized Interbody Implants in the Surgical Treatment of Adult Spinal Deformity

STUDY DESIGN

Multicenter cohort.

OBJECTIVES

A report from the International Spine Study Group (ISSG) noted that surgeons failed to achieve alignment goals in nearly two-thirds of 266 complex adult deformity surgery (CADS) cases. We assess whether personalized interbody spacers are associated with improved rates of achieving goal alignment following adult spinal deformity (ASD) surgery.

METHODS

ASD patients were included if their surgery utilized 3D-printed personalized interbody spacer(s) and they met ISSG CADS inclusion criteria. Planned alignment was personalized by the surgeon during interbody planning. Planned vs achieved alignment was assessed and compared with the ISSG CADS series that used stock interbodies.

RESULTS

For 65 patients with personalized interbodies, 62% were women, mean age was 70.3 years (SD = 8.3), mean instrumented levels was 9.9 (SD = 4.1), and the mean number of personalized interbodies per patient was 2.2 (SD = .8). Segmental alignment was achieved close to plan for levels with personalized interbodies, with mean difference between goal and achieved as follows: intervertebral lordosis = .9° (SD = 5.2°), intervertebral coronal angle = .1° (SD = 4.7°), and posterior disc height = -0.1 mm (SD = 2.3 mm). Achieved pelvic incidence-to-lumbar lordosis mismatch (PI-LL) correlated significantly with goal PI-LL (r = .668, P < .001). Compared with the ISSG CADS cohort, utilization of personalized interbodies resulted in significant improvement in achieving PI-LL <5° of plan (P = .046) and showed a significant reduction in cases with PI-LL >15° of plan (P = .012).

CONCLUSIONS

This study supports use of personalized interbodies as a means of better achieving goal segmental sagittal and coronal alignment and significantly improving achievement of goal PI-LL compared with stock devices.

Contemporary clinical perspectives on chronic low back pain: The biology, mechanics, etc. underpinning clinical and radiological evaluation

Background

Pain of a chronic nature remains the foremost concern in tertiary spine clinics, yet its elusive nature and quantification challenges persist. Despite extensive research and education on low back pain (LBP), the realm of diagnostic practices lacks a unified approach. Clinically, LBP exhibits a multifaceted character, encompassing conventional assessments of severity and disability, alongside nuanced attributes like pain characterization, duration, and patient expectations. Common instigators of LBP encountered in spine surgical settings comprise degenerated intervertebral discs (IVD), herniated IVD, canal and foraminal stenosis, and spondylolisthesis. However, addressing the root cause necessitates its identification and substantiation through visualization.

Methods

This perspective reviews the diagnostic complexities of LBP. Thorough history-taking and physical examinations offer preliminary insights into the underlying source of pain, whether it arises from discogenic origins, neural compression, or sagittal imbalance. The importance of classifying chronic LBP into the underlying pathophysiology is explored. Emphasis is placed on the necessity of aligning clinical observations with imaging findings to guide personalized treatment strategies.

Results

Currently, there exists a disparity globally between evidence-based recommendations and actual applications. Recent discoveries behind the pathophysiology of pain phenotypes signify the importance of classifying LBP into its neuropathic or nociceptive origins. The pivotal role of radiological investigations in validating clinical findings for an accurate diagnosis cannot be overstated. However, radiology should not operate in isolation; the disconnect between the clinical and radiological realms ultimately benefits neither the patient nor the surgeon. Additionally, more sensitive measures of IVD prolapse and the corresponding inflammatory pathway triggered are required to provide information on the underlying pathophysiological mechanism of pain generation.

Conclusion

This perspective article underscores the imperative fusion of clinical acumen and radiological precision in the intricate landscape of LBP diagnosis. These findings advocate for a paradigm shift towards personalized medicine. By offering a compass for surgeons to navigate this complex terrain and deliver more effective, patient-centered care with targeted interventions this article aims to enhance management outcomes for chronic LBP.

Patients Undergoing Multilevel Thoracolumbar Fusions With Prior Total Hip Arthroplasty Are at Higher Risk for Prosthetic Dislocations

BACKGROUND

As the number of patients undergoing both total hip arthroplasty (THA) and lumbar spinal fusion rises, clinicians must gain a stronger understanding of the biomechanical and clinical associations between these two procedures. This study compared single versus multilevel spinal fusion on spinopelvic parameters, clinical outcomes, and THA dislocation rates in patients with existing THAs.

METHODS

Patients with an existing THA undergoing elective spinal fusion were retrospectively identified at a single academic center. Cohorts were stratified by fusion construct length (single or multilevel) and outcomes were followed at least 1 year after surgery.

RESULTS

A total of 392 patients (260 single level, 132 multilevel) were included. Patients who underwent multilevel fusion had less improvement in ∆ visual analogue scale (VAS) Back Scores at 1 year (-1.00 vs. -2.50, P = 0.039), greater hospital length of stay (5.00 vs. 3.00 days, P < 0.001), and lower rates of discharge home (48.5% vs. 81.4%, P < 0.001). They had higher dislocation (4.55% vs. 0.38%, P = 0.007), spinal revision (25.8% vs. 13.5%, P = 0.004), and 90-day readmission rates (12.1% vs. 3.46%, P = 0.002). Radiographically, patients with multilevel constructs had lower preoperative (40.4° vs. 49.1°, P < 0.001), postoperative (43.4° vs. 48.6°, P = 0.004), and 1-year lumbar lordosis (44.4° vs. 50.5°, P = 0.028) and higher postoperative mean anteversion (24.2° vs. 21.0°, P = 0.017). Single-level fusion was an independent predictor for lower VAS leg scores (odds ratio [OR] = -2.57, P = 0.011), fewer readmissions (OR = -0.13, P = 0.001), and fewer complications (OR = -0.25, P < 0.001). Male sex independently predicted increased spinal revisions (OR = 0.13, P = 0.026).

CONCLUSION

Patients with prior THA undergoing multilevel fusions experienced more dislocations, higher spinal revisions, less frequent discharge home, longer hospital length of stays, and higher 90-day readmission rates. They had less improvement in ∆VAS Back Scores at 1 year, lower lumbar lordosis, and greater anteversion. Patients with existing THA undergoing multilevel fusion have more abnormal spinal sagittal balance and higher risk of dislocation despite higher baseline and postoperative acetabular anteversion.

Expandable versus static transforaminal lumbar interbody fusion (TLIF) cages: comparing radiographic outcomes and complication profiles

BACKGROUND CONTEXT

Expandable transforaminal lumbar interbody fusion (TLIF) cages have become popular in recent years due to anticipated advantages of increased disc height, improved segmental lordosis, and ease of implantation. Such benefits have not been conclusively demonstrated in the literature.

PURPOSE

To determine whether expandable cages increase disc height and segmental lordosis in a durable way following surgery and compare complication profiles between cage types.

STUDY DESIGN/SETTING

Retrospective cohort study conducted within a large academic health system involving 31 different spine surgeons.

PATIENT SAMPLE

Adults undergoing single-level TLIF for an indication other than infection, tumor, trauma, or revision instrumentation from 2021 to 2023.

OUTCOME MEASURES

Our primary outcomes were changes in segmental disc height, segmental lordosis, and L4-S1 lordosis at 2 weeks, 6 months, and 1 year following surgery relative to baseline. Our secondary outcomes were frequencies of incidental durotomies, surgical site infections, readmissions, death, subsidence, and unplanned return to the operating room.

METHODS

Radiographic variables were collected from our institutional imaging registry. Demographics and surgical characteristics were abstracted from chart review. Generalized linear modeling was used for each primary outcome, with cage type (expandable vs static) as our primary predictor and age, biologic sex, race, CCI, year of surgery, duration of surgery, invasiveness of surgery, surgeon specialty (Orthopedics vs Neurosurgery), and level of surgery as covariates.

RESULTS

Our cohort consisted of 417 patients with a mean age of 62. Static cages were used in 306 patients and expandable cages in 111. Expandable cages were associated with increased changes in disc height relative to static cages at 2 weeks (1.1 mm [0.2-1.9]; p=.01) and 6 months (1.2 mm [0.2-2.3]; p=.02) following surgery, but differences were no longer significant at 1 year (0.4 mm [-0.9-1.8]; p=.4). Expandable cages were found to subside more commonly than static cages (14.1% vs 6.6%; p=.04). No significant differences between cage types were identified in lordotic parameters at any timepoint (p=0.25 to p=0.97).

CONCLUSIONS

Expandable cages were associated with an initial increase in disc height relative to static cages, but this difference diminished with the first year of surgery, likely due to a higher rate of subsidence within the expandable cohort.

Enhancing the Technical Pearls for L5-S1 Anterior Lumbar Interbody Fusion in Patients with Body Mass Index More Than 30: Clinical and Radiographic Outcomes at 1-Year Follow-Up

BACKGROUND

Performing anterior lumbar interbody fusion (ALIF) in patients with a body mass index (BMI) >30 presents surgical challenges. To overcome those challenges, a modified procedure is described.

METHODS

This study retrospectively reviewed patients with a BMI >30 who underwent the modified L5-S1 ALIF procedure from August 2017 to September 2023. Patient demographic and operative characteristics were collected. Clinical and radiographic outcomes were analyzed before surgery and at 1-year follow-up. An analysis was performed comparing patients with a BMI >30 who underwent the modified ALIF procedure versus the standard ALIF procedure.

RESULTS

A total of 26 patients with BMI >30 were evaluated. Thirteen received treatment with the modified ALIF technique, and 13 received treatment with the standard ALIF technique. Operative time was significantly shorter in the modified ALIF technique cohort (P = 0.006). Preoperative and postoperative radiographic findings indicated significant differences in anterior disc height (P < 0.001), posterior disc height (P = 0.02), and L5-S1 segmental lordosis (P < 0.001) in patients undergoing the modified ALIF technique. There were no intraoperative complications. Postoperative visual analog scale for back pain, visual analog scale for leg pain, and Oswestry Disability Index scores significantly improved after surgery (P < 0.05) in both cohorts after 1 year. Complete interbody fusion was achieved according to computed tomography evaluation 1 year after surgery in more than 80% of cases.

CONCLUSIONS

ALIF surgery is a safe technique to address lumbar pathologies. This operative technique provides complimentary abdominal exposure data for access surgeons while performing ALIFs in patients with BMI >30. This technique could reduce operative time in such patients.

Use of Preoperative Spinal Angiography in Severe Spinal Deformity Patients Who Require Thoracic 3 Column Osteotomy: A Case Series and Review of the Literature

BACKGROUND AND OBJECTIVES

Three-column osteotomy (3CO) offers substantial spinal deformity correction. Thoracic neurovascular bundle sacrifice is often required, and anterior spinal artery (ASA) perfusion can be compromised. Spinal angiography allows localization of variable ASA vascular contribution. This study's objective was to describe a series of patients who underwent preoperative spinal angiography and discuss the impact on surgical planning and execution of thoracic 3CO for deformity correction.

METHODS

Patients who underwent preoperative spinal angiograms and thoracic 3CO for deformity correction were reviewed. Preoperative, angiographic, and postoperative information was recorded. A literature review on preoperative spinal angiography in deformity surgery was performed.

RESULTS

Eight patients were identified: single-level pedicle subtraction osteotomies (1), single-level vertebral column resections (2), and multilevel vertebral column resections (5). The average age was 40.0 years, and 75.0% were female. Thoracic scoliosis ranged from 0 to 105° preoperatively and 0 to 45.1° postoperatively. Thoracic kyphosis ranged from 29° to 120° preoperatively and 20.6° to 54.9° postoperatively. Twelve ASA supply vessels were identified bilaterally in 6 patients. Four patients had nontraditional ASA supply at T4 (1), T6 (1), and L2 (2), and 4 had multiple ASA feeders. Based on angiographic results, osteotomy site was changed (1), and neurovascular bundles were spared (2), a 37.5% rate of surgical plan alteration. There were no permanent neuromonitoring changes or postoperative neurologic deficits. No articles reported on using spinal angiography specifically for deformity surgery.

CONCLUSION

Spinal angiography is low risk and provides critical information regarding ASA supply to potentially mitigate ischemic risk during neurovascular bundle takedown during thoracic 3CO. Further case series are warranted to evaluate the benefits in larger populations, but its clinical applications appear practical.

Correlations between spinopelvic parameters and health-related quality of life in degenerative lumbar scoliosis patients before and after long -level fusion surgery

BACKGROUND

For degenerative lumbar scoliosis (DLS), prior studies mainly focused on the preoperative relationship between spinopelvic parameters and health-related quality of life (HRQoL), lacking an exhaustive evaluation of the postoperative situation. Therefore, the postoperative parameters most closely bonded with clinical outcomes has not yet been well-defined in DLS patients. The objective of this study was to comprehensively assess the correlation between radiographic parameters and HRQoL before and after surgery, and to identified the most valuable spinopelvic parameters for postoperative curative effect.

METHODS

This study retrospectively reviewed 130 consecutive patients who underwent long-level fusion with at least 1 year follow-up. Standing whole-spine radiographs and HRQoL measurements were examined preoperatively and at final follow-up. Spinopelvic parameters included thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), pelvic incidence minus lumbar lordosis (PI-LL), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), sagittal vertical axis (SVA), T1 pelvic angle (TPA), Global tilt (GT), Cobb angle (CA), apical vertebral translation (AVT) and coronal vertical axis (CVA). HRQoL was evaluated using the Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), Chinese version of Lumbar Stiffness Disability Index (C-LSDI), Japanese Orthopedic Association-29 (JOA-29), Scoliosis Research Society-22 (SRS-22),and the 36-item Short Form Health Survey (SF-36) total and subscale scores. Pearson's correlation analysis was performed to determine relationships between them.

RESULTS

The study population included 104 women and 26 men with an average age of 62.9 years. Both coronal and sagittal parameters showed significant correlations with HRQoL scores pre- and post-operatively. Among the coronal parameters, only CA showed correlations with SRS-22 subscale scores, and its correlation with Self-image scores were observed both before and after surgery. Among sagittal parameters, PT, PI-LL, LL, SVA, TPA, and GT showed significant correlations with HRQoL before surgery, including ODI, JOA-29, and SF-36 PCS. At final follow-up, except for AVT, CVA, and LL, all other sagittal parameters were significantly correlated with HRQoL.

CONCLUSIONS

HRQoL scores not only correlated with radiological parameters before surgery, but also after long-term follow-up. Besides, sagittal parameters, especially postoperative PI-LL, SVA, TPA, GT, were more closely correlated with clinical outcome measurements.

High Preoperative T1 Slope is a Marker for Global Sagittal Malalignment

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To develop parameter thresholds obtainable from cervical radiographs that correlate with concomitant thoracolumbar malalignment.

SUMMARY OF BACKGROUND DATA

T1 slope (T1S) is typically discussed in the context of cervical deformity and correlated with health-related quality of life outcomes. Prior research suggests that T1S is related to global alignment; however, a definition for "high" T1S has not been established. Most patients undergoing cervical surgery do not undergo full-spine imaging; therefore, obtaining a parameter associated with thoracolumbar malalignment from cervical radiographs would be beneficial.

METHODS

A database of preoperative adult spinal deformity (ASD) patients was analyzed. Measures obtained from standing lateral radiographs included T1S, thoracic kyphosis (TK), sagittal vertical axis (SVA), T1-pelvic angle (TPA), pelvic tilt (PT), and pelvic incidence minus lumbar lordosis (PI-LL). Decision tree analysis was then used to determine the T1S corresponding to published thresholds for high TK (40 degrees), SVA (40 mm), TPA (25 degrees), and PT (25 degrees). Alignment between high and normal T1S patients was compared.

RESULTS

Two hundred twenty-six preoperative patients were included (mean: 58±16 y 62%F). Larger T1S was correlated with greater SVA (r=0.365), TPA (r=0.302), TK (r=0.606), and PT (r=0.230) (all P<0.001). Decision tree analysis yielded a threshold of 30 degrees for high T1S, which 50% of patients had. Compared with patients with T1S <30 degrees, those with T1S >30 degrees had higher TK (41.5 vs. 25.8 degrees), SVA (78.7 vs. 33.7 mm), TPA (27.6 vs. 18.3 degrees), and PT (26.3 vs. 20.8 degrees), and PI-LL (18.2 vs. 11.7 degrees) (all P<0.05). Seventy-nine percent of patients with high T1S had high TK (T1S <30=13%), 69% had high SVA (T1S <30=38%), 66% had high TPA (T1S <30=37%), 60% had PT >25 degrees (T1S <30=42%), and 47% had PI-LL >20 degrees (T1S <30=34%) (all P<0.05).

CONCLUSION

Higher T1S was associated with worse global alignment. T1S was most strongly associated with TK. A T1S=30 degrees corresponded to high TK, SVA, TPA, and PT thresholds. Therefore, surgeons should consider obtaining full-spine radiographs if a T1S >30 degrees is present on cervical imaging.

Proximal Lumbar Anterior Column Realignment for Iatrogenic Sagittal Plane Adult Spinal Deformity Correction: A Retrospective Case Series

BACKGROUND

Anterior column realignment (ACR) is a powerful minimally invasive surgery technique to restore sagittal alignment in adult spinal deformity (ASD). This can accomplish similar segmental lordosis restoration as 3-column osteotomy with less blood loss and comparable complication rates. ACR can be performed at adjacent disease segments in the proximal lumbar spine in revision cases. However, two thirds of physiologic lordosis occurs between L4-S1, and concerns remain about altered lumbar morphology. We evaluated patients who underwent proximal lumbar ACR for iatrogenic flatback deformity.

METHODS

A total of 19 consecutive patients who underwent L1-2 or L2-3 ACR were retrospectively analyzed. All patients were treated with lateral minimally invasive surgery interbody technique, followed by posterior reconstruction with Smith-Peterson osteotomy. Preoperative and postoperative radiographic and clinical outcomes were obtained.

RESULTS

Mean follow-up was 19 months. All but 1 patient had a history of prior lumbar or lumbo-sacral fusion. Sagittal vertical axis and pelvic incidence-lumbar lordosis decreased from 11.9 cm to 6.1 cm (P < 0.0001) and 34.2° to 12.8° (P < 0.0001). Segmental lordosis increased from -2.7° to 21.9° (P < 0.0001). Proximal lumbar lordosis increased from -0.4° to 22.6° (P < 0.0001), and lordosis distribution index decreased from 79.5% to 48.9% (P < 0.0001). Mean Oswestry Disability Index and numeric pain rating scale back pain scores decreased from 58.0 to 36.2 (P = 0.0041) and 7.9 to 3.4 (P < 0.0001), respectively. Patient-Reported Outcomes Measurement Information System Physical and Mental Health T-scores increased from 34.1 to 43.3 (P = 0.0049) and 40.4 to 45.0 (P = 0.0993), respectively. Major complication rate was 15.8%. One patient required revision for mechanical failure. There were no permanent neurological or vascular injuries.

CONCLUSIONS

Proximal lumbar ACR plus Smith-Peterson osteotomy can achieve sagittal correction with low major complication rates in patients with ASD and prior distal fusion. Differentially increasing proximal lumbar lordosis and lowering lumbar distribution index did not have deleterious effects on radiographic or clinical outcomes. Further work is needed to understand the effect of proximal ACR in the surgical management of ASD.

Incidence and Risk Factors of Lumbosacral Complications Following Long-Segment Spinal Fusion in Adult Degenerative Scoliosis

PURPOSE

Long-segment spinal fusions are associated with lumbosacral complications (LSC), but the associated risk factors are not known. This study aimed to identify the risk factors for LSC after long-segment instrumented fusion with distal fixation to the L5 vertebral body in adult degenerative scoliosis (ADS).

METHODS

We retrospectively evaluated 294 patients with ADS who underwent long-segment floating fusion between January 2014 and March 2022, with follow-up for at least 2 years. Patients were matched to the baseline data using fusion level > 5 as a grouping variable. Patients who completed matching were divided into two groups according to the presence or absence of LSC. Univariate logistic regression was applied to identify potential risk factors for LSC, and multivariate logistic regression was used to identify independent risk factors for postoperative LSC.

RESULTS

The overall incidence of LSC was 21.77% in the 294 patients, with disc degeneration in 28 (9.52%) and radiographic ASD in 44 (14.97%) patients. The mean time to LSC development after surgery was 26.91 ± 8.43 months. A total of 54 pairs of patients were matched and grouped, and the complication group had higher Oswestry Disability Index (ODI) and visual analog scale (VAS) scores at the last follow-up. Multivariate analysis showed that gender (OR = 0.274, p = 0.026 [0.087, 0.859]); levels of fusion > 5 (OR = 3.127, p = 0.029 [1.120, 8.730]), main curve correction rate (OR = 0.009, p = 0.005 [0.000, 0.330]), and postoperative pelvic incidence minus lumbar lordosis (PI-LL) > 15° (OR = 3.346, p = 0.022 [1.195, 9.373]) were independent risk factors for postoperative LSC. The area under the curve value of the prediction model was 0.804, with a 95% confidence interval of 0.715-0.892, indicating that the model had a high prediction accuracy. Collinearity statistics showed no collinearity between variables.

CONCLUSION

Sex, level of fusion > 5, main curve correction rate, and postoperative PI-LL > 15° were independent risk factors for the development of LSC after long-segment floating fusion. These results will improve our ability to predict personal risk conditions and provide better medical optimisation for surgery.

Quantitative assessment of muscle activity of back and lower extremities, whole body sagittal alignment, body sway, and health-related quality of life in adult spinal deformity patients before and after spinopelvic correction surgery: From the standpoint of the "cone of economy"

BACKGROUND AND AIMS

Pain and muscle fatigue in the low back and lower extremity associated with adult spinal deformity (ASD) markedly limit daily activities and affect quality of life. This study aimed to clarify if spinal correction surgery decreases the muscle activity requirements in relation to alignment and balance parameters.

METHODS

Integrated electromyogram (I-EMG) studies of the low back and lower extremity in addition to whole body alignment, body sway, and health-related quality of life (HRQOL) were evaluated in 16 patients with ASD before and after surgery. Sixteen healthy volunteers were included as control subjects. Muscle activities of the bilateral lumbar paravertebral, biceps femoris, rectus femoris, gastrocnemius, and tibialis anterior were measured using surface electromyogram in both resting and working standing positions. Surgical outcomes were based on improvements in muscle fatigue using the sum of the whole muscle I-EMGs and body sway. HRQOL was evaluated by SRS-22r, which measures 4 domains (function, pain, self-image, mental health) and subtotal scores.

RESULTS

In controls, the sum of the 10 whole I-EMGs (mVms; mean ± SD) was 3316 ± 1247 in the resting standing position and 5625 ± 2065 in the working standing position. The I-EMG values were higher in ASD patients than in healthy subjects; in the resting standing position, the sum of the whole 10 I-EMGs significantly decreased from baseline (9125 ± 3529) to 3 (6088 ± 1793) and 6 (6381 ± 1776) months postoperatively (p < 0.01). In the working standing position, the sum in ASD patients also significantly decreased from baseline (14,160 ± 5474) to 3 (8085 ± 2540) and 6 (8557 ± 3025) months postoperatively (p < 0.01). I-EMG values did not differ significantly between the 3- and 6-month time points in either condition. Body sway was also improved postoperatively at 3 months and maintained at 6 months along with the amelioration of whole-body sagittal alignment, and 4 domains and subtotal SRS-22r scores significantly increased postoperatively.

CONCLUSION

Following spinopelvic correction surgery, whole body sagittal alignment was improved, and muscle activity based on I-EMG and body sway were significantly decreased. The SRS-22r scores after surgery also indicated significant improvement, suggesting that muscle fatigue in the standing position was ameliorated, i.e., the "cone of economy" was normalized.

Which components of the global alignment proportionality score have the greatest impact on outcomes in adult spinal deformity corrective surgery?

PURPOSE

To investigate the impact of the Global Alignment and Proportion (GAP) score components on patient outcomes in Adult Spine Deformity (ASD) surgery.

METHODS

Patients included underwent assessment via the GAP score and its individual components: pelvic version (GAP PV), lumbar lordosis (GAP LL), lumbar distribution index (GAP LDI) and spinopelvic component (GAP SP). Multivariable analyses assessed the association between alignment in these components and clinical outcomes in ASD patients.

RESULTS

762 ASD patients met inclusion criteria. Alignment in GAP SP independently predicted meeting MCID for SR-22S and ODI and was associated with a lower likelihood of developing mechanical complications. Patients aligned in GAP SP were less likely to develop proximal junctional kyphosis (OR 0.42, 0.26-0.73, p = 0.01) and PJF (OR 0.3, 0.13-0.74, p = 0.01). Proportioned alignment in GAP SP with disproportioned alignment in GAP LDI contributed to an increased risk of PJK and PJF (OR 2.67, 95% CI 1.95-6.82, p = 0.045). There was no significant association of GAP SP proportionality and GAP RPV (OR 1.1, 0.86-2.15, p = 0.253) or GAP LL (OR 1.34, 0.78-4.23, p = 0.673) disproportionality with outcomes. Disproportioned alignment in GAP SP but proportioned alignment in both GAP LL and GAP LDI was associated with decreased likelihood of PJK (OR 0.53, 95% CI 0.39-0.94, p = 0.02) and PJF (OR 0.31, 95% CI 0.19-0.67, p = 0.001).

CONCLUSION

The spinopelvic component of the GAP score is the most significant independent predictor of clinical outcomes. Its interaction with the other components of the GAP score also aids assessment of the risk for mechanical complications.

The Effect of Changes in Segmental Lordosis on Global Lumbar and Adjacent Segment Lordosis After L5-S1 Anterior Lumbar Interbody Fusion

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

Restoration of lordosis in lumbar fusion reduces low back pain, decreases adjacent segment degeneration, and improves postoperative outcomes. However, the potential effects of changes in segmental lordosis on adjacent-level and global lordosis remain less understood. This study aims to examine the relationships between segmental (SL), adjacent-level, and global lumbar lordosis following L5-S1 Anterior Lumbar Interbody Fusion (ALIF).

METHODS

80 consecutive patients who underwent single-level L5-S1 ALIF were divided into 3 groups based on the degree of change (∆) in index-level segmental lordosis: <5° (n = 23), 5°-10° (n = 29), >10° (n = 28). Radiographic parameters measured included global lumbar, segmental, and adjacent level lordosis, sacral slope, pelvic tilt, pelvic incidence, and PI-LL mismatch.

RESULTS

Patients with ∆SL 5°-10° or ∆SL >10° both showed significant increases in global lumbar lordosis from preoperative to final follow-up. However, patients with ∆SL >10° showed statistically significant losses in adjacent level lordosis at both immediate postoperative and final follow-up compared to preoperative. When comparing patients with ∆SL >10° to those with ∆SL 5-10°, there were no significant differences in global lumbar lordosis at final follow-up, due to significantly greater losses of adjacent level lordosis in these patients.

CONCLUSION

The degree of compensatory loss of lordosis at the adjacent level L4-L5 correlated with the extent of segmental lordosis creation at the index L5-S1 level. This may suggest that the L4 to S1 segment acts as a "harmonious unit," able to accommodate only a certain amount of lordosis and further increases in segmental lordosis may be mitigated by loss of adjacent-level lordosis.

Distal Lumbar Lordosis is Associated With Reoperation for Adjacent Segment Disease After Lumbar Fusion for Degenerative Conditions

STUDY DESIGN

A single centre retrospective review.

OBJECTIVE

Recent studies have suggested that distal lordosis (L4-S1, DL) remains constant across all pelvic incidence (PI) subgroups, whilst proximal lordosis (L1-L4, PL) varies. We sought to investigate the impact of post-operative DL on adjacent segment disease (ASD) requiring reoperation in patients undergoing lumbar fusion for degenerative conditions.

METHODS

Patients undergoing 1-3 level lumbar fusion with the two senior authors between 2007-16 were included. Demographic and radiographic data were recorded. Univariate, multivariate binary logistic regression, and Kaplan Meier survivorship analyses were performed.

RESULTS

335 patients were included in the final analysis. Most had single (67%) or two (31%) level fusions. The mean follow-up was 64-month. Fifty-seven patients (17%) underwent reoperation for ASD at an average of 78-month post-operatively (R group). The R group had a significantly lower mean post-operative DL (27.3 vs 31.1 deg, P < .001) and mean PI (55.5 vs 59.2 deg, P < .05). On univariate analysis, patients with a post-operative DL of <35 deg had higher odds of reoperation for ASD than those with a post-operative DL of ≥35 deg (OR 2.7, P = .016). In the multivariate model, post-operative DL, low/average PI, and spondylolisthesis were all significantly associated with reoperation for ASD.

CONCLUSION

This study provides preliminary support to an association between post-operative distal lumbar lordosis and risk of reoperation for ASD in patients undergoing fusions for degenerative conditions. Further multicentre prospective study is needed to independently confirm this association and identify the impact of restoration of physiological distal lumbar lordosis on long term patient outcomes.

Effect of romosozumab administration on proximal junctional kyphosis in corrective spinal fusion surgery

BACKGROUND CONTEXT

The effect of romosozumab administration in patients undergoing corrective spinal fusion surgery has not yet been analyzed.

PURPOSE

To examine the effect of romosozumab administration on reducing the incidence of proximal junctional kyphosis (PJK), particularly PJK due to fractures (PJK-Fx), in patients undergoing spinal corrective fusion surgery.

DESIGN

Retrospective cohort study PATIENT SAMPLE: A total of 111 patients aged >50 years underwent corrective fusion surgery (>2 vertebrae) for adult spinal deformity or vertebral compression fracture between June 2010 and July 2023.

OUTCOME MEASURES

The primary outcome was the incidence of PJK, whereas the secondary outcomes were changes in Hounsfield unit (HU) values, surgical complications, and clinical outcomes measured using the Japanese Orthopaedic Association (JOA) and visual analog scale scores.

METHODS

The patients were divided into the romosozumab (n=32) and non-romosozumab groups (n=79). Romosozumab was typically administered 2 months before surgery in the romosozumab group. Demographic data, surgery-related factors, and radiographic parameters were analyzed. HU values at the upper instrumented vertebra+1 (UIV+1) were measured preoperatively and at 1 year postoperatively. After the univariate analysis of preoperative factors associated with PJK, multivariate logistic regression was used to identify factors associated with PJK.

RESULTS

Romosozumab significantly increased the HU values at UIV+1 (-1.22% vs. 13.60%, p<0.001) and reduced the incidence of PJK (39.24% vs. 18.75%, p=0.046), particularly PJK-Fx (26.58% vs. 6.25%, p=0.019) and osteoporosis-related complications (55.70% vs. 34.38%, p=0.011). The multivariate analysis showed a significantly lower incidence of PJK (adjusted odds ratio = 0.32, p=0.033), particularly PJK-Fx (adjusted odds ratio = 0.15, p=0.018). There was a tendency for better JOA scores at 1 year postoperatively in the romosozumab group (21.49 vs. 23.62, p=0.071).

CONCLUSION

Romosozumab administration effectively increased bone density and reduced the risk of PJK, particularly PJK-Fx, and osteoporosis-related complications in patients undergoing corrective spinal fusion surgery. Administration of romosozumab 2 months before surgery enhanced bone mineral density and strength, leading to better surgical outcomes and fewer complications. Further long-term studies are needed to confirm these findings and optimize treatment protocols.

Risk Factor Analysis of Mechanical Complications in Surgical Treatment of Thoracolumbar Deformity with Osteoporotic Vertebral Fracture

Objective: Adult spinal deformity (ASD) with osteoporotic vertebral fractures (OVF) often requires vertebral body resection and replacement. However, postoperative mechanical complications (MC) have been unsolved issues. This study retrospectively investigated the risk of MC following anterior-posterior spinal fusion (APF) with vertebral body resection and replacement for OVF with ASD. Methods: Among 91 cases undergoing APF with vertebral body resection and replacement, 43 cases met the deformity criteria. The mean age was 74.2 years, and the mean number of fused segments was 5.7. Pre and postoperative spinal alignments were measured, and the risk of MC occurrence, including PJK, DJK, and cage sinking, was determined through multivariate analysis. The AUC and cutoff values were calculated through ROC analysis. Results: The incidence of MC, PJK, and DJK were 28%, 12%, and 14%, respectively. Multivariate analysis for MC revealed postoperative PI-LL and operative time (cutoff: 40.5 degrees, 238 min) as significant risk factors, while postoperative PI-LL was a significant risk factor for PJK (cutoff: 42.4 degrees). Evaluation considering only thoracolumbar level showed postoperative local kyphosis as a significant MC risk factor (cutoff: 11 degrees). There was a positive correlation between operative time and preoperative local kyphosis, with a cutoff value of 238 min being equivalent to 21 degrees. Conclusion: The postoperative mismatch over 40 degrees and preoperative local kyphosis over 21 degrees were considered as a high risk for MCs. The postoperative kyphosis of 11 degrees was the risk factor of MC in the thoracolumbar level. The meticulous preoperative assessment, including local and global alignment, and local flexibility as well as detailed surgical planning of fixation range and the requirement of osteotomy, are crucial.

Preoperative Radiographic Predictors of Subsequent Fusion After Lumbar Decompression Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The purpose of this study is to determine which demographic, surgical, and radiographic preoperative characteristics are most associated with the need for subsequent fusion after decompression lumbar spinal surgery.

SUMMARY OF BACKGROUND DATA

There is a relatively high rate of the need for repeat decompression or fusion after an index decompression procedure for degenerative spine disease. Nevertheless, there is a dearth of literature identifying risk factors for lumbar fusion following decompression surgery.

METHODS

Patients 18 years or older receiving a primary lumbar decompression surgery within the levels of L3-S1 between 2011 and 2020 were identified. All patients had preoperative radiographs and 2 years of follow-up data. Chart review was performed for surgical characteristics and demographics. The sagittal parameters included lumbar lordosis (LL), segmental lordosis (SL), anterior disk height (aDH), posterior disk height (pDH), sacral slope (SS), and pelvic tilt (PT). Pelvic incidence (PI=PT+SS) and pelvic incidence minus lumbar lordosis (PI-LL) were calculated. In addition, the Roussouly classification was determined for each patient. Bivariant and multivariant analyses were performed.

RESULTS

Of the 363 patients identified in this study, 96 patients had a fusion after their index decompression surgery. Multivariable analysis identified involvement of L4-L5 level in the decompression [odds ratio (OR)=1.83 (1.09-3.14), P =0.026], increased L5-S1 segmental lordosis [OR=1.08 (1.03-1.13), P =0.001], decreased SS [OR=0.96 (0.93-0.99), P =0.023], and decreased endplate obliquity [OR=0.88 (0.77-0.99), P =0.040] as significant independent predictors of fusion after decompression surgery.

CONCLUSIONS

This is one of the first studies to assess preoperative sagittal parameters in conjunction with demographic variables to determine predictors of the need for fusion after index decompression. We demonstrated that decompression at L4-L5, greater L5-S1 segmental lordosis, decreased sacral slope, and decreased endplate obliquity were associated with higher rates of fusion after decompression surgery.

Efficacy of intervertebral release combined with asymmetric osteotomy in rigid degenerative scoliosis

PURPOSE

The aim of this study is to evaluate the clinical efficacy and safety of treating patients with rigid degenerative scoliosis by restoring intervertebral balance through a combination of interbody release and asymmetric grade 1 and 2 osteotomy.

METHOD

The medical collected clinical and radiographic data of patients with rigid degenerative scoliosis from our department between 2015 and 2022. A total of 60 patients were included in the study, comprising 20 males and 40 females, with an average follow-up period of 30.7 months. Data recorded included surgery duration, blood loss, number of fixed segments, hospital stay, complications, clinical scores, and radiographic parameters.

RESULTS

The sagittal vertical axis improved from 4.28 ± 1.48 cm preoperatively to 2.90 ± 1.18 cm postoperatively, while the coronal vertical axis improved from 3.29 ± 1.72 cm preoperatively to 1.12 ± 0.62 cm postoperatively. The preoperative coronal Cobb angle was 30.85 ± 7.33°, which improved to 4.14 ± 3.06°postoperatively. Additionally, lumbar lordosis increased from 24.50 ± 17.24°preoperatively to 30.35 ± 6.11°postoperatively. VAS scores for back pain and leg pain, ODI scores, and JOA scores showed varying degrees of improvement.

CONCLUSION

Interbody release combined with asymmetric Grade 1 and 2 osteotomy to restore intervertebral balance significantly improves spinal deformity and postoperative functional scores in patients with rigid degenerative scoliosis.

Establishing a comprehensive care paradigm: Insights from a specialised combined scoliosis clinic in Australia

Orthopaedic spine surgery, particularly for adult spinal deformity, demands extensive expertise due to its complex pathologies. Surgical success hinges on precise planning, multidisciplinary collaboration, and advanced techniques to correct deformities and restore spinal alignment. This study investigates the efficacy of a Combined Monthly Scoliosis Clinic initiated in April 2022 at Spine Service, St George Private Hospital. The clinic integrates adult and paediatric spine surgeons from Sydney, aiming to provide specialized care and educational opportunities. Patient assessments include physical evaluations and tailored imaging, with treatment strategies discussed collaboratively amongst surgeons, fellows, registrars and students. Over an 18-month period, the clinic assessed 41 patients (average age 50.4 years; 61.0 % female) with diverse spinal conditions. Treatment approaches varied, encompassing spinal fusion, decompression, and conservative management tailored to individual pathologies. The Combined Monthly Scoliosis Clinic exemplifies a comprehensive model for managing complex spinal deformities. It emphasizes collaborative diagnostics, personalized treatment planning, and continuous educational enhancement for trainees and fellows. Patient outcomes underscore the clinic's effectiveness in improving quality of life through tailored interventions. This integrated approach sets a benchmark for global spine care centres, ensuring optimal patient-centric care and advancing clinical standards through ongoing feedback and adaptation.

Clinical Analysis and Imaging Study of Lateral Lumbar Intervertebral Fusion in the Treatment of Degenerative Lumbar Scoliosis

OBJECTIVE

As the population ages and technology advances, lateral lumbar intervertebral fusion (LLIF) is gaining popularity for the treatment of degenerative lumbar scoliosis (DLS). This study investigated the feasibility, minimally invasive concept, and benefits of LLIF for the treatment of DLS by observing and assessing the clinical efficacy, imaging changes, and complications following the procedure.

METHODS

A retrospective analysis was performed for 52 DLS patients (12 men and 40 women, aged 65.84 ± 9.873 years) who underwent LLIF from January 2019 to January 2023. The operation time, blood loss, complications, clinical efficacy indicators (visual analogue scale [VAS], Oswestry disability index [ODI], and 36-Item Short Form Survey), and imaging indicators (coronal position: Cobb angle and center sacral vertical line-C7 plumbline [CSVL-C7PL]; and sagittal position: sagittal vertical axis [SVA], lumbar lordosis [LL], pelvic incidence angle [PI], and thoracic kyphosis angle [TK] were measured). All patients were followed up. The above clinical evaluation indexes and imaging outcomes of patients postoperatively and at last follow-up were compared to their preoperative results.

RESULTS

Compared to the preoperative values, the Cobb angle and LL angle were significantly improved after surgery (p < 0.001). Meanwhile, CSVL-C7PL, SVA, and TK did not change much after surgery (p > 0.05) but improved significantly at follow-up (p < 0.001). There was no significant change in PI at either the postoperative or follow-up timepoint. The operation took 283.90 ± 81.62 min and resulted in a total blood loss of 257.27 ± 213.44 mL. No significant complications occurred. Patients were followed up for to 21.7 ± 9.8 months. VAS, ODI, and SF-36 scores improved considerably at postoperative and final follow-up compared to preoperative levels (p < 0.001). After surgery, the Cobb angle and LL angle had improved significantly compared to preoperative values (p < 0.001). CSVL-C7PL, SVA, and TK were stable after surgery (p > 0.05) but considerably improved during follow-up (p < 0.001). PI showed no significant change at either the postoperative or follow-up timepoints.

CONCLUSION

Lateral lumbar intervertebral fusion treatment of DLS significantly improved sagittal and coronal balance of the lumbar spine, as well as compensatory thoracic scoliosis, with good clinical and radiological findings. Furthermore, there was less blood, less trauma, and quicker recovery from surgery.

Global Coronal Malalignment in Degenerative Lumbar Scoliosis and Priority-Matching Correction Technique to Prevent Postoperative Coronal Decompensation

STUDY DESIGN

A prospective case-control study.

OBJECTIVE

To analyze global coronal malalignment (GCM) in degenerative lumbar scoliosis (DLS) and to prospectively investigate the performance of priority-matching correction technique on preventing postoperative coronal imbalance.

METHODS

A total of 444 DLS inpatients and outpatients were recruited. GCMs were classified into 2 types: Type 1, GCM with thoracolumbar (TL/L) curve as the main contribution on coronal imbalance; Type 2, GCM with lumbosacral (LS) curve as the main contribution on coronal imbalance. Patients receiving priority-matching correction were assigned to Group P-M and receiving traditional correction were assigned to Group T form August 2020. The fundamental principle of priority-matching technique was to first correct the key curve contributing to coronal imbalance rather than the curve with greater magnitude.

RESULTS

Type 1 GCM accounted for 45% and Type 2 GCM accounted for 55% of patients. Type 2 GCM was detected to have greater LS Cobb angle and L4 tilt. At 1-year follow-up, 29.8% of patients with Type 2 GCM, whereas 11.7% of patients with Type 1 GCM were observed to have postoperative coronal decompensation. Patients with postoperative imbalance were revealed to have greater preoperative LS Cobb angle and L4 tilt and smaller correction extent of LS curve and L4 tilt. 6.25% of patients developed postoperative coronal imbalance in Group P-M, whereas 40.5% developed in Group T.

CONCLUSION

Highlighting priority and aggressive correction of the key curve to coronal imbalance, priority-matching technique was proved to be able to limit the development of postoperative coronal decompensation.

Longitudinal impact of multi-segment spinal fixation surgery on mobility status and clinical outcomes in adult spinal deformity: a multicenter retrospective study

PURPOSE

To investigate changes in postoperative mobility status in patients with ASD, and the determining factors that influence these changes and their impact on clinical outcomes, including the rate of home discharge and long-term mobility.

METHODS

A total of 299 patients with ASD who underwent multi-segment posterior spinal fusion were registered in a multi-center database were investigated. Patient mobility status was assessed using walking aids and classified into five levels (1: independent, 2: cane, 3: walker, 4: assisted, and 5: wheelchair) preoperatively, at discharge, and after 2 years. We determined improvements or declines in the patient's mobility based on changes in the classification levels. The analysis focused on the factors contributing to the deterioration of postoperative mobility.

RESULTS

Two years postoperatively, 87% of patients maintained or improved mobility. However, 27% showed decreased mobility status at discharge, associated with a lower rate of home discharge (49% vs. 80% in the maintained mobility group) and limited improvement in mobility status (35% vs. 5%) after 2 years. Notably, postoperative increases in thoracic kyphosis (7.0 ± 12.1 vs. 2.0 ± 12.4°, p = 0.002) and lower lumbar lordosis (4.2 ± 13.1 vs. 1.8 ± 12.6°, p = 0.050) were substantial factors in mobility decline.

CONCLUSION

Postoperative mobility often temporarily decreases but generally improves after 2 years. However, an overcorrection in sagittal alignment, evidenced by increased TK, could detrimentally affect patients' mobility status. Transient mobility decline associated with overcorrection may require further rehabilitation or hospitalization. Further studies are required to determine the biomechanical effects of surgical correction on mobility.

Preoperative Planning of Lumbar Lordosis for Adult Degenerative Scoliosis Surgery in the Chinese Population

OBJECTIVE

Pelvic incidence minus lumbar lordosis mismatch (PI-LL) is directly related to poor quality of life in adult degenerative scoliosis (ADS) patients. The purpose of the study was to determine the most appropriate postoperative PI-LL value for patients with ADS.

METHODS

The medical records of patients with ADS in our department were retrospectively collected. The data included age, sex, body mass index, age-adjusted Charlson comorbidity index, osteopenia, length of hospital stay, operative duration, estimated blood loss, American Society of Anesthesiologists score, number of fusion levels, lumbar lordosis, sagittal vertical axis, pelvic incidence, PI-LL, Scoliosis Research Society-22 score, Oswestry Disability Index score, and mechanical complications.

RESULTS

A total of 316 patients were enrolled. PI-LL, lumbar lordosis, sagittal vertical axis, Scoliosis Research Society-22 score, Oswestry Disability Index score at the time of last follow-up were 20.7 ± 8.5°, 23.4 ± 14.1°, 4.0 ± 2.1 cm, 3.7 ± 0.9, and 18.1 ± 5.5, respectively. In terms of mechanical complications, 88 patients (27.8%), 34 patients (10.8%), and 19 patients (6.0%) had proximal junctional kyphosis, distal junctional kyphosis, and implant-related complications, respectively. In the fully adjusted model, compared with 0 grade PI-LL group and ++ grade PI-LL group, + grade PI-LL group had the best clinical outcomes and the fewest mechanical complications. The stability of these conclusions was verified in sensitivity analyses.

CONCLUSIONS

Optimal PI-LL value should be 10°-20° after corrective surgery in patients with ADS, which is associated with excellent clinical outcomes and lower complication rates. Previous criteria may be at risk of overcorrection, which may lead to proximal junctional kyphosis.

The Impact of L4-L5 Minimally Invasive Transforaminal Lumbar Interbody Fusion on 2-Year Adjacent-level Parameters

OBJECTIVE

This study evaluates the impact of L4-L5 minimally invasive surgery (MIS)- transforaminal lumbar interbody fusion (TLIF) on adjacent-level parameters.

METHODS

This is a retrospective study performed on consecutive patients between January 2015 and December 2019. The index- and adjacent-level segmental lordosis (SL) and disc angle (DA) were measured. Patient-reported outcomes (PROs) were collected preoperatively and at 3-24 months postoperatively. Factors influencing changes in adjacent-level parameters and the occurrence of adjacent segment degeneration (ASDeg) were assessed.

RESULTS

A total of 117 adult patients, averaging 65.5 years of age and slight preponderance of female (56.4%), were analyzed. L4-L5 SL decreased at 2 years (P < 0.05), but L4-L5 DA significantly increased at all timepoints (P < 0.05). While L3-L4 SL and DA significantly decreased at all timepoints (P < 0.05), L5-S1 SL decreased at 3 and 12 months (P < 0.05) and L5-S1 DA only significantly decreased at 2 years (P < 0.05). All PROs improved significantly (P < 0.0001). The ASDeg rate was 19.7% at 2.2 years. Cephalad and caudal ASDeg rates were 12.0% and 10.3%, respectively. Eight patients (6.8%) required adjacent-level reoperations, mainly at L3-L4 (6 cases). The use of expandable cage significantly reduced the odds of caudal ASDeg (OR 0.15, P = 0.037), but had no significant effect on cephalad ASDeg.

CONCLUSIONS

L4-L5 MIS-TLIF had a more consistent effect on L3-L4 than L5-S1. Although adjacent-level SL and DA decreased over time, their association with ASDeg appears limited, suggesting a multifactorial etiology. L4-L5 MIS-TLIF provides demonstrable clinical benefits with lasting PRO improvements and low adjacent-level reoperations.

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

PURPOSE

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.

METHODS

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 60 years 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 2 years postoperative mobility statuses were investigated.

RESULTS

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 2 years after surgery (P = 0.085).

CONCLUSION

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.

Sarcopenia Predicts the Development of Early Adjacent Segment Disease After Transforaminal Lumbar Interbody Fusion

BACKGROUND AND OBJECTIVES

Predicting the development of adjacent segment disease (ASD) after lumbar spine fusion would help guide preoperative and postoperative therapies to prevent reoperation. We sought to evaluate whether sarcopenia predicts the development of early ASD after transforaminal lumbar interbody fusion (TLIF).

METHODS

Retrospective data were collected from 109 patients who underwent TLIF from 2013 to 2023. Patients older than 18 years who underwent elective posterior midline approach TLIF were included. Patients with prior lumbar instrumented fusions, cases of trauma, central nervous system infection, cancer, or long-construct thoracolumbar deformity corrections and those who lacked sufficient follow-up were excluded. The primary outcome was radiographic ASD development within 3 years of surgery. Psoas volumetric measurements were recorded from the most recent preoperative MRI. Odds ratios were calculated with logistic regression analyses.

RESULTS

In 109 patients undergoing elective TLIF, 22 (20.2%) developed ASD within 3 years. Gender, body mass index, and extent of surgery were not associated with ASD development. Multivariate analysis showed left/right psoas cross-sectional area, and psoas:vertebral body ratio (P:VBR) predicted early ASD (P < .0001). Sarcopenia was further categorized as having bilateral P:VBR ≥1 SD below gender mean (T-score -1). Of 18 sarcopenic patients, 15 developed early ASD (83.33%) vs 7 of 91 nonsarcopenic patients (7.69%; P < .0001). Postoperative mismatch between pelvic incidence and lumbar lordosis was predictive of ASD on univariate (P = .0480) but not multivariate analysis. Pelvic tilt and lumbar lordosis postoperatively were not associated with early ASD.

CONCLUSION

Sarcopenia, measured by decreased psoas area and P:VBR, predicts ASD formation within 3 years of surgery. Morphometric analysis of psoas size is a simple tool to identify patients at risk of developing ASD. This information can potentially guide preoperative and postoperative therapies, affect surgical decision making, and effectively counsel patients on risks of reoperation.

Incidence and Risk Factors of Sacral Fracture Following Lumbosacral Fusion for Degenerative Spinal Stenosis with a Minimum Follow-Up of 2 Years: A Case-Control Study

BACKGROUND

This study aimed to investigate the incidence and risk factors for sacral fractures following lumbosacral fusion.

METHODS

We conducted a retrospective review of patients who underwent lumbosacral fusion for degenerative spinal stenosis with a minimum follow-up of 2 years. Patients who developed and those who did not develop a sacral fracture were categorized into the "sacral fracture" and "nonfracture" groups. The demographic and radiological data were compared between the 2 groups.

RESULTS

A total of 65 patients were included in this study. Among them, 7 patients were categorized into the sacral fracture and 58 patients into the nonfracture groups, respectively. The incidence of sacral fracture was 10.8%. In the sacral fracture group, age and fusion levels were significantly higher (P<0.05), while bone mineral density (BMD) T-score was significantly lower (P<0.05) than nonfracture group. Pelvic incidence, preoperative pelvic tilt, postoperative sacral slope, and postoperative lumbar lordosis were significantly higher (P<0.05) in the sacral fracture than the nonfracture group. Multivariable logistic regression analysis showed that BMD T-score (odds ratio [OR] 0.25, 95% confidence interval [CI] 0.08-0.79, P = 0.019), postoperative sacral slope (OR 1.14, 95% CI 1.00-1.29, P = 0.047), and changes in L4-S1 lordosis (OR 1.11, 95% CI 1.00-1.23, P = 0.049) were significant factors.

CONCLUSIONS

The overall incidence of sacral fracture was 10.8%. In our study, advanced age, low BMD, long fusion levels, and preoperative compensatory pelvic retroversion and excessive correction of it were risk factors for sacral fractures.

Analysis of the reliability of KEOPS version 2 for the measurement of coronal and sagittal parameters in spinal deformity

BACKGROUND

The purpose of the study is to evaluate the updated version of this software in patients with various spinal deformity.

METHODS

Sixty patients were included in this study and were divided into three categories: 20 patients with AIS, 20 patients with ASD, and 20 patients having undergone corrective surgery for spinal deformity. The measurements were performed by two senior and two junior orthopedic surgery residents, and were done at two points in time separated by a 3-week interval with the cases being randomized every time to reduce the risk of memory bias. Measured parameters included coronal, sagittal, global alignment parameters, and pelvic parameters.

RESULTS

When assessing the inter- and intra-observer reliability across all the groups of patients, none of the coefficients was smaller than 0.8 with a very high level of agreement. The standard error ranged from 0.7° to 1.5° demonstrating a high level of accuracy. Fairly similar results were seen when the groups were divided into the three categories except for the post-operative groups where a strong and not perfect level of agreement was reported.

CONCLUSION

This is the first study to assess the reproducibility of the new version of KEOPS, showing a very high agreement in all measurements. In the post-operative group, although it showed a strong agreement, the lower performance can be explained by the presence of surgical material making it harder to identify the anatomical landmarks accurately. Nevertheless, we can recommend the usage of this software in a clinical setting.

Impact of pelvic anteversion on spinopelvic alignment in an asymptomatic population: a dynamic perspective of standing and sitting

BACKGROUND CONTEXT

A subgroup of patients with pelvic anteversion can present with an unusually large degree of lumbar lordosis (LL), a highly sloped sacrum, and a relatively small pelvic incidence (PI). Prior to lumbar surgery, it can be important to consider such unique sagittal alignment. However, until now, there has been a lack of a predictive model considering different pelvic alignments. Furthermore, the dynamic characteristics of an anteverted pelvis (AP) subgroup have also been unclear.

PURPOSE

To build linear predictive formulas for LL that take pelvic anteversion into consideration and to explore the dynamic characteristics of an AP subgroup.

STUDY DESIGN

Monocentric, cross-sectional study.

PATIENT SAMPLE

Five hundred sixty-five asymptomatic Chinese men and women between the ages of 18 and 80 years.

OUTCOME MEASURES

Sagittal parameters including LL, lumbar lordosis minus thoracic kyphosis (LL-TK), PI, pelvic tilt (PT), pelvic incidence minus lumbar lordosis (PI-LL), sacral slope (SS), sacral slope divided by pelvic incidence (SS/PI), sagittal vertical axis (SVA), thoracic kyphosis (TK), and T1 (first thoracic vertebra) pelvic angle (TPA) were measured on whole spine radiographs obtained with participants in standing and sitting positions.

METHODS

All participants underwent radiography in the standing position; 235 of them underwent additional radiography in the sitting position to allow measurement of sagittal parameters. The participants with pelvic anteversion were placed in an AP (anteverted pelvis) group. Sagittal parameters were compared between the AP group and the non-AP group, and predictive formulas for LL based on PI were created in both groups. In addition, changes in sagittal parameters from standing to sitting were compared in the AP group and a PI-matched control group.

RESULTS

Of the 565 participants, 171 (30.3%) had pelvic anteversion. In comparison with the non-AP group, the AP group presented with larger LL, a larger SS, and a smaller PT, with relatively small PI. The predictive formulas for LL were LL=0.60° × PI+21.60° (R2=0.268; p<.001) in the whole cohort, LL=0. 83×PI+18.75° (R2=0.427; p<.001) in AP group, and LL=0.79°×PI+9.66° (R2=0.451; p<.001) in the non-AP group. In moving from standing to sitting, the AP group presented with a larger decrease in SS and LL compared with the control group, indicating different patterns of spinopelvic motion.

CONCLUSIONS

In the cohort examined, 30.3% present with pelvic anteversion. Those with AP present with unique characteristics of spinopelvic alignment. In moving from standing to sitting, they exhibit different patterns of spinopelvic motion. We found that identifying the degree of anteversion in each person improves the accuracy of linear models for predicting the degree of LL, which in turn can make plans for spine surgery more accurate.

How Good Are Surgeons at Achieving Their Preoperative Goal Sagittal Alignment Following Adult Deformity Surgery?

STUDY DESIGN

Multicenter, prospective cohort.

OBJECTIVES

Malalignment following adult spine deformity (ASD) surgery can impact outcomes and increase mechanical complications. We assess whether preoperative goals for sagittal alignment following ASD surgery are achieved.

METHODS

ASD patients were prospectively enrolled based on 3 criteria: deformity severity (PI-LL ≥25°, TPA ≥30°, SVA ≥15 cm, TCobb≥70° or TLCobb≥50°), procedure complexity (≥12 levels fused, 3-CO or ACR) and/or age (>65 and ≥7 levels fused). The surgeon documented sagittal alignment goals prior to surgery. Goals were compared with achieved alignment on first follow-up standing radiographs.

RESULTS

The 266 enrolled patients had a mean age of 61.0 years (SD = 14.6) and 68% were women. Mean instrumented levels was 13.6 (SD = 3.8), and 23.2% had a 3-CO. Mean (SD) offsets (achieved-goal) were: SVA = -8.5 mm (45.6 mm), PI-LL = -4.6° (14.6°), TK = 7.2° (14.7°), reflecting tendencies to undercorrect SVA and PI-LL and increase TK. Goals were achieved for SVA, PI-LL, and TK in 74.4%, 71.4%, and 68.8% of patients, respectively, and was achieved for all 3 parameters in 37.2% of patients. Three factors were independently associated with achievement of all 3 alignment goals: use of PACs/equivalent for surgical planning (P < .001), lower baseline GCA (P = .009), and surgery not including a 3-CO (P = .037).

CONCLUSIONS

Surgeons failed to achieve goal alignment of each sagittal parameter in ∼25-30% of ASD patients. Goal alignment for all 3 parameters was only achieved in 37.2% of patients. Those at greatest risk were patients with more severe deformity. Advancements are needed to enable more consistent translation of preoperative alignment goals to the operating room.