Reciprocal changes in sagittal spinal alignment after L5-S1 anterior lumbar interbody fusion.

OBJECTIVE: Degenerative diseases of the lumbar spine decrease lumbar lordosis (LL). Anterior lumbar interbody fusion (ALIF) at the L5-S1 disc space improves segmental lordosis, LL, and sagittal balance. This study investigated reciprocal changes in spinopelvic alignment after L5-S1 ALIF. METHODS: A retrospective chart review identified patients who underwent L5-S1 ALIF with or without posterior fixation at a single institution (November 1, 2016-October 1, 2021). Changes in pelvic tilt, sacral slope, proximal LL (L1-L4), distal LL (L4-S1), total LL (L1-S1), segmental lordosis, pelvic incidence-LL mismatch, thoracic kyphosis, cervical lordosis, and sagittal vertical axis were measured on preoperative and postoperative radiographs. RESULTS: Forty-eight patients were identified. Immediate postoperative radiographs were obtained at a mean (SD) of 17 (20) days after surgery; delayed radiographs were obtained 184 (82) days after surgery. After surgery, patients had significantly decreased pelvic tilt (15.71° [7.25°] vs 17.52° [7.67°], p=0.003) and proximal LL (11.86° [10.67°] vs 16.03° [10.45°], p<0.001) and increased sacral slope (39.49° [9.27°] vs 36.31° [10.39°], p<0.001), LL (55.35° [13.15°] vs 51.63° [13.38°], p=0.001), and distal LL (43.17° [9.33°] vs 35.80° [8.02°], p<0.001). Segmental lordosis increased significantly at L5-S1 and decreased significantly at L2-3, L3-4, and L4-5. Lordosis distribution index increased from 72.55 (19.53) to 81.38 (22.83) (p<0.001). CONCLUSIONS: L5-S1 ALIF was associated with increased L5-S1 segmental lordosis accompanied by pelvic anteversion and a reciprocal decrease in proximal lumbar lordosis. These changes may represent a reversal of compensatory mechanisms, suggesting an overall relaxation of spinopelvic alignment after L5-S1 ALIF.

Surgical Management of Hip-Spine Syndrome: A Systematic Review of the Literature.

INTRODUCTION: Hip-spine syndrome (HSS) was first described in 1983 to describe the symptomatology resulting from concomitant lumbar degenerative stenosis and hip osteoarthritis. Numerous studies have sought to understand the underlying pathology and appropriate management of this syndrome. The purpose of this article is to review the literature for specific imaging characteristics and the optimal surgical treatment of hip-spine syndrome (HSS). METHODS: A systematic review was conducted via an electronic database search through PubMed to identify all publications related to hip-spine syndrome. All publications that contained data on patients who underwent surgical treatment for hip-spine syndrome and reported patient-reported outcome measures (PROMs) or radiographic data were included. Exclusion criteria consisted of publications published in a language other than English, review articles, and technique articles. RESULTS: Fifteen articles that focused on the surgical management of HSS were identified. Of these 15 articles, eight reported radiographic outcomes with most reporting no significant change in spinopelvic parameters before and after surgery. Thirteen articles reported clinical outcomes, with eight of those thirteen articles identifying PROMs to be significantly improved following surgery. CONCLUSIONS: Despite being first described almost forty years ago, the data on surgical management of HSS remains sparse. While there is some evidence that total hip arthroplasty in patients who previously underwent spinal fusion may have higher complication rates, there remains debate regarding which surgical problem to address first - the hip or the spine.

Associating T1-Weighted and T2-Weighted Magnetic Resonance Imaging Radiomic Signatures With Preoperative Symptom Severity in Patients With Cervical Spondylotic Myelopathy.

BACKGROUND: Preoperative symptom severity in cervical spondylotic myelopathy (CSM) can be variable. Radiomic signatures could provide an imaging biomarker for symptom severity in CSM. This study utilizes radiomic signatures of T1-weighted and T2-weighted magnetic resonance imaging images to correlate with preoperative symptom severity based on modified Japanese Orthopaedic Association (mJOA) scores for patients with CSM. METHODS: Sixty-two patients with CSM were identified. Preoperative T1-weighted and T2-weighted magnetic resonance imaging images for each patient were segmented from C2-C7. A total of 205 texture features were extracted from each volume of interest. After feature normalization, each second-order feature was further subdivided to yield a total of 400 features from each volume of interest for analysis. Supervised machine learning was used to build radiomic models. RESULTS: The patient cohort had a median mJOA preoperative score of 13; of which, 30 patients had a score of >13 (low severity) and 32 patients had a score of ≤13 (high severity). Radiomic analysis of T2-weighted imaging resulted in 4 radiomic signatures that correlated with preoperative mJOA with a sensitivity, specificity, and accuracy of 78%, 89%, and 83%, respectively (P < 0.004). The area under the curve value for the ROC curves were 0.69, 0.70, and 0.77 for models generated by independent T1 texture features, T1 and T2 texture features in combination, and independent T2 texture features, respectively. CONCLUSIONS: Radiomic models correlate with preoperative mJOA scores using T2 texture features in patients with CSM. This may serve as a surrogate, objective imaging biomarker to measure the preoperative functional status of patients.

Stable Regional and Global Alignment in Patients Treated With Minimally Invasive Lateral Retropleural Thoracic Diskectomy Without Fixation.

BACKGROUND AND OBJECTIVES: Thoracic disk herniations are challenging to treat, and open transthoracic or minimally invasive thoracoscopic approaches are associated with significant morbidity, substantial costs, and steep learning curves. The minimally invasive lateral retropleural thoracic diskectomy (MIS-LRP-TD) approach is straightforward and is associated with lower perioperative morbidity. With MIS-LRP-TD, the overlying rib, ipsilateral pedicle, ligamentum flavum, posterior longitudinal ligament, and posterior third of the adjacent vertebral bodies are resected. Adjunct fixation is typically not performed, eliminating hardware-related complications and costs. This radiographic study investigates long-term global and thoracic spine alignment after MIS-LRP-TD without fixation. METHODS: This study was a single-institution, retrospective evaluation of all patients who underwent MIS-LRP-TD without fixation between November 7, 2017 and July 19, 2022. Preoperative and the most recent postoperative radiographs were used to determine the C7 plumb line to central sacral vertical line, thoracic Cobb angle (TCA), segmental Cobb angle, C7 to sagittal vertical axis, thoracic kyphosis, and segmental kyphosis. RESULTS: In total, 22 patients with 24 disk herniations underwent MIS-LRP-TD without fixation. The mean (SD) radiographic follow-up was 12.9 (11.2) months. Overall, no significant differences were seen in C7 plumb line to central sacral vertical line (P = .65), C7 to sagittal vertical axis (P = .99), thoracic kyphosis (P = .30), TCA (P = .28), segmental kyphosis (P = .27), or segmental Cobb angle (P = .56) at follow-up. One patient demonstrated a >5° change in TCA but remained asymptomatic. CONCLUSION: Despite requiring extensive resection of the middle column and ipsilateral costovertebral joint at the index level, MIS-LRP-TD without adjunct fixation does not lead to significant global, regional, or segmental deformity. Thus, MIS-LRP-TD appears to be a safe, effective treatment approach for challenging thoracic disk herniations.

Social Determinants of Health Impact Spinal Cord Injury Outcomes in Low- and Middle-Income Countries: A Meta-Epidemiological Study.

BACKGROUND AND OBJECTIVES: Traumatic spinal cord injuries (SCI), which disproportionally occur in low- and middle-income countries (LMICs), pose a significant global health challenge. Despite the prevalence and severity of SCI in these settings, access to appropriate surgical care and barriers to treatment remain poorly understood on a global scale, with data from LMICs being particularly scarce and underreported. This study sought to examine the impact of social determinants of health (SDoH) on the pooled in-hospital and follow-up mortality, and neurological outcomes, after SCI in LMICs. METHODS: A systematic review was conducted in adherence to the Preferred Reporting in Systematic Review and Meta-Analysis-guidelines. Multivariable analysis was performed by multivariable linear regression, investigating the impact of the parameters of interest (patient demographics, country SDoH characteristics) on major patient outcomes (in-hospital/follow-up mortality, neurological dysfunction). RESULTS: Forty-five (N = 45) studies were included for analysis, representing 13 individual countries and 18 134 total patients. The aggregate pooled in-hospital mortality rate was 6.46% and 17.29% at follow-up. The in-hospital severe neurological dysfunction rate was 97.64% and 57.36% at follow-up. Patients with rural injury had a nearly 4 times greater rate of severe in-hospital neurological deficits than patients in urban areas. The Gini index, reflective of income inequality, was associated with a 23.8% increase in in-hospital mortality, a 20.1% decrease in neurological dysfunction at follow-up, and a 12.9% increase in mortality at follow-up. CONCLUSION: This study demonstrates the prevalence of injury and impact of SDoH on major patient outcomes after SCI in LMICs. Future initiatives may use these findings to design global solutions for more equitable care of patients with SCI.

A comparison of modern-era anterior lumbar interbody fusion and minimally invasive transforaminal lumbar interbody fusion at the lumbosacral junction.

OBJECTIVE: Interbody fusion is the primary method for achieving arthrodesis across the lumbosacral junction in the setting of degenerative pathologies, such as spondylosis and spondylolisthesis. Two common techniques are anterior lumbar interbody fusion (ALIF) and posterior transforaminal lumbar interbody fusion (TLIF). In recent years, interbody design and technology have advanced, and most earlier studies comparing ALIF and TLIF did not specifically assess the lumbosacral junction. This study compared changes in radiographic and clinical parameters between patients undergoing modern-era single-level ALIF and minimally invasive surgery (MIS) TLIF at L5-S1. METHODS: Consecutive patients who underwent single-segment L5-S1 ALIF or MIS TLIF performed by the senior authors over a 6-year interval (January 1, 2016-November 30, 2021) were retrospectively reviewed. Upright radiographs were used to determine pre- and postoperative lumbar lordosis, segmental lordosis, disc angle, and neuroforaminal height. Improvements in patient-reported outcome scores (Oswestry Disability Index and SF-36) were also compared. RESULTS: Overall, 108 patients (58 [54%] men, 50 [46%] women; mean [SD] age 57.6 [13.5] years) were included in the study. ALIF was performed in 49 patients, and TLIF was performed in 59 patients. The most common treatment indications were spondylolisthesis (50%, 54/108) and spondylosis (46%, 50/108). The cohorts did not differ in terms of intraoperative (p > 0.99) or postoperative (p = 0.73) complication rates. The mean (SD) hospital length of stay was significantly shorter for patients undergoing TLIF than ALIF (1.3 [0.6] days vs 2.0 [1.4] days, p < 0.001). Both techniques significantly improved L5-S1 segmental lordosis, disc angle, and neuroforaminal height (p ≤ 0.008). ALIF versus TLIF significantly increased mean [SD] segmental lordosis (12.5° [7.3°] vs 2.0° [5.7°], p < 0.001), disc angle (14.8° [5.5°] vs 3.0° [6.1°], p < 0.001), and neuroforaminal height (4.5 [4.6] mm vs 2.4 [3.0] mm, p = 0.008). Improvements in patient-reported outcome parameters and reoperation rates were similar between cohorts. CONCLUSIONS: When treating patients at a single segment across the lumbosacral junction, ALIF resulted in significantly greater increases in segmental lordosis, L5-S1 disc angle, and neuroforaminal height compared with MIS TLIF. Improvements in clinical parameters and reoperation rates were similar between the 2 techniques.

Bilateral sacroiliac joint fusion in long constructs using self-harvesting porous S2-alar iliac screws with an integrated tulip: technical considerations and early clinical and radiographic experience.

OBJECTIVE: The incidence of sacroiliac joint (SIJ) dysfunction after lumbosacral fusion is high. Upfront bilateral SIJ fusion using novel fenestrated self-harvesting porous S2-alar iliac (S2AI) screws could reduce the incidence of SIJ dysfunction and need for subsequent SIJ fusion. In this study, the authors report their early clinical and radiographic results of SIJ fusion using this novel screw. METHODS: The authors began using self-harvesting porous screws in July 2022. This is a retrospective review of consecutive patients at a single institution who underwent long thoracolumbar surgery with extension to the pelvis using this porous screw. Radiographic parameters of regional and global alignment were collected preoperatively and at the time of last follow-up. The incidence of intraoperative complications and need for revision were collected. The incidences of mechanical complications, including screw breakage, implant loosening/pullout, and screw cap dislocation at the time of last follow-up were also collected. RESULTS: Ten patients with a mean age of 67 years were included, 6 of whom were male. Seven patients had a thoracolumbar construct with extension to the pelvis. Three patients had upper instrumented vertebrae at the proximal lumbar spine. Intraoperative breach was not encountered in any of the patients (0%). Postoperatively, 1 patient (10%) had screw breakage at the neck of the tulip of the modified iliac screw discovered at routine follow-up without clinical sequalae. CONCLUSIONS: Use of self-harvesting porous S2AI screws incorporated into long thoracolumbar constructs was safe and feasible, demanding unique technical considerations. Long-term clinical and radiographic follow-up with a large patient cohort is necessary to determine their durability and efficacy to achieve SIJ arthrodesis and prevent SIJ dysfunction.

Durability of stand-alone anterolateral interbody fusion in staged minimally invasive circumferential scoliosis surgery with delayed posterior instrumentation due to medical necessity.

PURPOSE: Circumferential minimally invasive scoliosis surgeries are often staged, wherein anterior and/or lateral lumbar interbody fusion is followed by percutaneous posterior fixation days later. This study examines the impact on outcomes when posterior augmentation was delayed due to unexpected medical issues following the first stage, anterolateral procedure. METHODS: A retrospective review was conducted of all patients undergoing minimally invasive circumferential deformity corrections from 2006 to 2019. Patients in whom planned posterior fixation was postponed due to medical necessity or safety concerns were identified. Perioperative surgical metrics and radiographic parameters were collected. RESULTS: Three of the six patients initially scheduled for circumferential fusion never underwent posterior augmentation due to symptomatic improvement (2.3, 5, and 10.7 years of follow-up). The other three underwent posterior fixation once medically optimized after an average interval of 4.7 months (range 3.2-7.8 months) due to persistent symptoms. It was also observed that the average coronal malalignment in the postoperative period was 5.1 cm in the group requiring further fixation and only 1.6 cm in the group which did not. CONCLUSION: In select cases, the indirect decompression and stability conferred by minimally invasive anterolateral arthrodesis alone may afford adequate pain relief to delay or even avoid posterior fixation in patients with adult spinal deformity.

Top-ten most-cited articles on anterior column release in the context of minimally invasive lumbar interbody fusion.

Introduction: Lateral anterior column release (ACR) is a minimally invasive option for the correction of sagittal plane deformity. To assemble a homogeneous picture of published research on ACR, an advanced bibliometric analysis was conducted to compile the top-ten most-cited articles on the topic of ACR. Methods: A keyword search using the Thomson Reuters Web of Knowledge was conducted to identify articles discussing the role of lateral ACR. The articles were then ranked based on the total number of citations to identify the ten most-cited articles published. A subjective appraisal of the findings of these articles was conducted to provide a ranked literature review and to examine trends in the study of ACR between 2012 and 2019. Results: The earliest published article on ACR was in 2012 by Deukmedjian et al. Three articles were in vitro biomechanical assessments of ACR, and seven articles were on outcome analyses, which were either case series or case controlled. The most-cited article was a biomechanical study authored by Uribe et al. The article with the highest rate of citations/year was authored by Manwaring et al. Uribe and the European Spine Journal were the most frequently cited author and journal, respectively. Conclusions: The lateral ACR approach has enjoyed significant scholarly attention since its advent. Higher-level analyses with robust control groups, larger sample sizes, and long-term follow-up are necessary to improve our understanding of this approach.

Minimally Invasive Surgery Strategies to Prevent Proximal Junctional Kyphosis.

Proximal junctional kyphosis (PJK) is a common complication following long-segment thoracolumbar fusions for patients with adult spinal deformities. PJK is described as a progressive kyphosis at the upper instrumented vertebra or 1 or 2 segments adjacent to the instrumented vertebra. This condition can lead to proximal junction failure, which results in vertebral body fractures, screw pullouts, and neurological deficits. Revision surgery is necessary to address symptomatic PJK. Research efforts have been dedicated to elucidating risk factors and prevention strategies. It has been postulated that minimally invasive surgery (MIS) techniques may help prevent PJK because these techniques aim to preserve the soft tissue integrity at the top of the construct and maintain posterior element support. In this article, the authors define PJK, describe MIS strategies to prevent PJK, and compare PJK rates after MIS with PJK rates after open approaches for long-segment thoracolumbar fusion.

Complications associated with single-position prone lateral lumbar interbody fusion: a systematic review and pooled analysis.

OBJECTIVE: Lateral lumbar interbody fusion (LLIF) is a workhorse surgical approach for lumbar arthrodesis. There is growing interest in techniques for performing single-position surgery in which LLIF and pedicle screw fixation are performed with the patient in the prone position. Most studies of prone LLIF are of poor quality and without long-term follow-up; therefore, the complication profile related to this novel approach is not well known. The objective of this study was to perform a systematic review and pooled analysis to understand the safety profile of prone LLIF. METHODS: A systematic review of the literature and a pooled analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All studies reporting prone LLIF were assessed for inclusion. Studies not reporting complication rates were excluded. RESULTS: Ten studies meeting the inclusion criteria were analyzed. Overall, 286 patients were treated with prone LLIF across these studies, and a mean (SD) of 1.3 (0.2) levels per patient were treated. The 18 intraoperative complications reported included cage subsidence (3.8% [3/78]), anterior longitudinal ligament rupture (2.3% [5/215]), cage repositioning (2.1% [2/95]), segmental artery injury (2.0% [5/244]), aborted prone interbody placement (0.8% [2/244]), and durotomy (0.6% [1/156]). No major vascular or peritoneal injuries were reported. Sixty-eight postoperative complications occurred, including hip flexor weakness (17.8% [21/118]), thigh and groin sensory symptoms (13.3% [31/233]), revision surgery (3.8% [3/78]), wound infection (1.9% [3/156]), psoas hematoma (1.3% [2/156]), and motor neural injury (1.2% [2/166]). CONCLUSIONS: Single-position LLIF in the prone position appears to be a safe surgical approach with a low complication profile. Longer-term follow-up and prospective studies are needed to better characterize the long-term complication rates related to this approach.

Graft subsidence and reoperation after lateral lumbar interbody fusion: a propensity score-matched and cost analysis of polyetheretherketone versus 3D-printed porous titanium interbodies.

OBJECTIVE: Lumbar interbody cage subsidence has a multifactorial etiology. Cage material, although well studied after transforaminal lumbar interbody fusion, has not been investigated as a contributing factor to subsidence after lateral lumbar interbody fusion (LLIF). In this study the authors compared rates of subsidence and reoperation after LLIF between polyetheretherketone (PEEK) and 3D-printed porous titanium (pTi) in an institutional propensity score-matched and cost analysis. METHODS: This is a retrospective observational cohort analysis of adult patients who underwent LLIF with pTi versus PEEK between 2016 and 2020. Demographic, clinical, and radiographic characteristics were collected. Propensity scores were calculated and 1:1 matching without replacement of surgically treated levels was performed. The primary outcome of interest was subsidence. The Marchi subsidence grade was determined at the time of last follow-up. Chi-square or Fisher's exact tests were used to compare subsidence and reoperation rates between lumbar levels treated with PEEK versus pTi. Modeling and cost analysis were performed using TreeAge Pro Healthcare. RESULTS: The authors identified a total of 192 patients; 137 underwent LLIF with PEEK (212 levels) and 55 had LLIF with pTi (97 levels). After propensity score matching, a total of 97 lumbar levels remained in each treatment group. After matching, there were no statistically significant differences between groups in baseline characteristics. Levels treated with pTi were significantly less likely to exhibit subsidence (any grade) compared to those treated with PEEK (8% vs 27%, p = 0.001). Five (5.2%) levels treated with PEEK required reoperation for subsidence, but only 1 (1.0%) level treated with pTi required reoperation for subsidence (p = 0.12). Given subsidence and revision rates experienced in the cohorts in this study, the pTi interbody device is economically superior to PEEK in a single-level LLIF as long as its cost is at least $1185.94 lower than that of PEEK. CONCLUSIONS: The pTi interbody device was associated with less subsidence, but statistically similar revision rates after LLIF. pTi is potentially a superior economic choice at this study's reported revision rate.

Direct Iliac Screw vs Sacral-2-Alar-Iliac Screws Technique for Sacropelvic Fixation: Technical Nuances and a Review of the Literature.

Sacropelvic (SP) fixation is the immobilization of the sacroiliac joint to attain lumbosacral fusion and prevent distal spinal junctional failure. SP fixation is indicated in numerous spinal conditions (eg, scoliosis, multilevel spondylolisthesis, spinal/sacral trauma, tumors, or infections). Many SP fixation techniques have been described in the literature. Currently, the most used surgical techniques for SP fixation are direct iliac screws and sacral-2-alar-iliac screws. There is currently no consensus in the literature on which technique carries more favorable clinical outcomes. In this review, we aim to assess the available data on each technique and discuss their respective advantages and disadvantages. We will also present our experience with a modification of direct iliac screws using a subcrestal approach and outline the future prospects of SP fixation.

Clinical Validation of a Novel Musculoskeletal Modeling Framework to Predict Postoperative Sagittal Alignment.

STUDY DESIGN: A retrospective radiographic and biomechanical analysis of 108 thoracolumbar fusion patients from two clinical centers. OBJECTIVE: This study aimed to determine the validity of a computational framework for predicting postoperative patient posture based on preoperative imaging and surgical data in a large clinical sample. SUMMARY OF BACKGROUND DATA: Short-term and long-term studies on thoracolumbar fusion patients have discussed that a preoperative predictive model would benefit surgical planning and improve patient outcomes. Clinical studies have shown that postoperative alignment changes at the pelvis and intact spine levels may negatively affect postural balance and quality of life. However, it remains challenging to predict such changes preoperatively because of confounding surgical and patient factors. MATERIALS AND METHODS: Patient-specific musculoskeletal models incorporated weight, height, body mass index, age, pathology-associated muscle strength, preoperative sagittal alignment, and surgical treatment details. The sagittal alignment parameters predicted by the simulations were compared with those observed radiographically at a minimum of three months after surgery. RESULTS: Pearson correlation coefficients ranged from r=0.86 to 0.95, and mean errors ranged from 4.1° to 5.6°. The predictive accuracies for postoperative spinopelvic malalignment (pelvic incidence minus lumbar lordosis>10°) and sagittal imbalance parameters (TPA>14°, T9PA>7.4°, or LPA>7.2°) were between 81% and 94%. Patients treated with long fusion (greater than five segments) had relatively lower prediction errors for lumbar lordosis and spinopelvic mismatch than those in the local and short groups. CONCLUSIONS: The overall model performance with long constructs was superior to those of the local (one to two segments) and short (three to four segments) fusion cases. The clinical framework is a promising tool in development to enhance clinical judgment and to help design treatment strategies for predictable surgical outcomes. LEVEL OF EVIDENCE: 3.

The 'candy cane' technique for construct augmentation and correction of severe angular chin-on-chest kyphoscoliosis.

PURPOSE: To manage severe angular chin-on-chest deformity. METHODS: A single midline incision and periosteal dissection were utilized to expose from C2 to T6. Bilateral C2 pars screws, C3 to C7 lateral mass screws, and T1 to T6 pedicle screws were placed. Following the placement of screws, multiple two column posterior osteotomies and interlaminar decompressions from C6 to T3 were performed to amplify both the sagittal and coronal corrections. Titanium rods were utilized in light of the patient's known osteopenia and nickel allergy. As such, the construct was augmented via the use of a third accessory rod. This third titanium rod was placed into a supplementary translaminar screw with three connectors to the right-sided main rod. Once the lordotic configuration of the contralateral main rod was secured, an additional corrective maneuver of gentle distraction across this third rod was employed to assist with coronal correction. RESULTS: In this patient with osteopenia, a known nickel allergy, and significant cervical imbalance, the Candy Cane construct allowed for a durable correction of the severe sagittal and coronal plane deformity. The chin-brow angle was corrected by 44°. The coronal Cobb angle improved by 10°. On long-term follow-up, the patient reported continued satisfaction with the operation and was able to perform his activities of daily living. CONCLUSION: A one-stage, posterior approach along with construct augmentation, with a third rod hooked into a supplementary C2 translaminar screw, can be employed for the correction of chin-on-chest kyphoscoliosis.

Long-Term Durability of Stand-Alone Lateral Lumbar Interbody Fusion.

BACKGROUND: The long-term durability of stand-alone lateral lumbar interbody fusion (LLIF) remains unknown. OBJECTIVE: To evaluate whether early patient-reported outcome measures after stand-alone LLIF are sustained on long-term follow-up. METHODS: One hundred and twenty-six patients who underwent stand-alone LLIF between 2009 and 2017 were included in this study. Patient-reported outcome measures included the Oswestry Disability Index (ODI), EuroQOL-5D (EQ-5D), and visual analog score (VAS) scores. Durable outcomes were defined as scores showing a significant improvement between preoperative and 6-week scores without demonstrating any significant decline at future time points. A repeated measures analysis was conducted using generalized estimating equations (model) to assess the outcome across different postoperative time points, including 6 weeks, 1 year, 2 years, and 5 years. RESULTS: ODI scores showed durable improvement at 5-year follow-up, with scores improving from 46.9 to 38.5 ( P = .001). Improvements in EQ-5D showed similar durability up to 5 years, improving from 0.48 to 0.65 ( P = .03). VAS scores also demonstrated significant improvements postoperatively that were durable at 2-year follow-up, improving from 7.0 to 4.6 ( P < .0001). CONCLUSION: Patients undergoing stand-alone LLIF were found to have significant improvements in ODI and EQ-5D at 6-week follow-up that remained durable up to 5 years postoperatively. VAS scores were found to be significantly improved at 6 weeks and up to 2 years postoperatively but failed to reach significance at 5 years. These findings demonstrate that patients undergoing stand-alone LLIF show significant improvement in overall disability after surgery that remains durable at long-term follow-up.

Crossing the Bridge From Degeneration to Deformity: When Does Sagittal Correction Impact Outcomes in Adult Spinal Deformity Surgery?

BACKGROUND: Patients with less severe adult spinal deformity (ASD) undergo surgical correction and often achieve good clinical outcomes. However, it is not well understood how much clinical improvement is due to sagittal correction rather than treatment of the spondylotic process. PURPOSE: Determine baseline thresholds in radiographic parameters that, when exceeded, may result in substantive clinical improvement from surgical correction. STUDY DESIGN: Retrospective. MATERIALS AND METHODS: ASD patients with BL and two-year data were included. Parameters assessed: sagittal vertical axis, pelvic incidence-lumbar lordosis mismatch, pelvic tilt, T1 pelvic angle, L1 pelvic angle, L4-S1 lordosis, C2-C7 sagittal vertical axis, C2-T3, C2 slope. Outcomes: Good Outcome (GO) at two years: [meeting either: (1) Substantial Clinical Benefit for Oswestry Disability Index (change >18.8), or (2) Oswestry Disability Index <15 and Scoliosis Research Society Total>4.5]. Binary logistic regression assessed each parameter to determine if correction was more likely needed to achieve GO. Conditional inference tree run machine learning analysis generated baseline thresholds for each parameter, above which, correction was necessary to achieve GO. RESULTS: We included 431 ASD patients. There were 223 (50%) that achieved a GO by two years. Binary logistic regression analysis demonstrated, with increasing baseline severity in deformity, sagittal correction was more often seen in those achieving GO for each parameter(all P <0.001). Of patients with baseline T1 pelvic angle above the threshold, 95% required correction to meet GO (95% vs. 54%, P <0.001). A baseline pelvic incidence-lumbar lordosis >10° (74% of patients meeting GO) needed correction to achieve GO (odds ratio: 2.6, 95% confidence interval: 1.4-4.8). A baseline C2 slope >15° also necessitated correction to obtain clinical success (odds ratio: 7.7, 95% confidence interval: 3.7-15.7). CONCLUSIONS: Our study highlighted point may be present at which sagittal correction has an outsized influence on clinical improvement, reflecting the line where deformity becomes a significant contributor to disability. These new thresholds give us insight into which patients may be more suitable for sagittal correction, as opposed to intervention for the spondylotic process only, leading to a more efficient utility of surgical intervention for ASD.

Surgical treatment of young adults with idiopathic scoliosis.

OBJECTIVE: In this study, the authors report on their experience with the surgical treatment of young adults with idiopathic scoliosis (YAdISs) who did not have surgical treatment in adolescence but did require intervention after skeletal maturity. METHODS: The medical records of YAdISs between 18 and 40 years of age who had been surgically treated at two institutions between 2009 and 2018 were retrospectively evaluated. Pre- and postoperative clinical and radiographic information was gathered and compared at 2 years after treatment. RESULTS: Twenty-eight patients (9 male, 19 female) with a median age of 25 years (range 18-40 years) met the study inclusion criteria. Five patients (18%) had postoperative complications, including 2 deep venous thromboses, 1 ileus, and 2 reoperations, one for implant failure and the other for pseudarthrosis. The mean maximum coronal curve angle improved from 43° ± 12° to 17° ± 8° (p < 0.001), but there were no significant differences in sagittal vertical axis, lumbar lordosis, pelvic tilt, or thoracic kyphosis (p > 0.05). There was no relationship between the amount of correction obtained and patient age (p = 0.46). Significant improvements in the Oswestry Disability Index (31 vs 24, p = 0.02), visual analog scale score for both back pain (6.0 vs 4.0, p = 0.01) and leg pain (2.6 vs 1.1, p = 0.02), and self-image score (Δ1.1, p < 0.001) were seen. CONCLUSIONS: YAdISs can present with pain, deformity progression, and/or appearance dissatisfaction because of their scoliosis despite successful nonoperative management during adolescence. Once the scoliosis becomes symptomatic, surgical correction can result in significant clinical and radiographic improvements at the 2-year follow-up with a relatively low complication rate compared to that for other types of adult spinal deformity.