Fusion For Adult Spinal Deformity Research Articles

Association of frailty with healthcare resource utilization after open thoracic/thoracolumbar posterior spinal fusion for adult spinal deformity.

The Hospital Frailty Risk Score (HFRS) is a frailty-identifying metric developed using ICD-10-CM codes. While other studies have examined frailty in adult spinal deformity (ASD), the HFRS has not been assessed in this population. The aim of this study was to utilize the HFRS to investigate the impact of frailty on outcomes in ASD patients undergoing posterior spinal fusion (PSF). A retrospective study was performed using the 2016-2019 National Inpatient Sample database. Adults with ASD undergoing elective PSF were identified using ICD-10-CM codes. Patients were categorized into HFRS-based frailty cohorts: Low (HFRS < 5) and Intermediate-High (HFRS ≥ 5). Patient demographics, comorbidities, intraoperative variables, and outcomes were assessed. Multivariate regression analyses were used to determine whether HFRS independently predicted extended length of stay (LOS), non-routine discharge, and increased cost. Of the 7500 patients identified, 4000 (53.3%) were in the Low HFRS cohort and 3500 (46.7%) were in the Intermediate-High HFRS cohort. On average, age increased progressively with increasing HFRS scores (p < 0.001). The frail cohort experienced more postoperative adverse events (p < 0.001), greater LOS (p < 0.001), accrued greater admission costs (p < 0.001), and had a higher rate of non-routine discharge (p < 0.001). On multivariate analysis, Intermediate-High HFRS was independently associated with extended LOS (OR: 2.58, p < 0.001) and non-routine discharge (OR: 1.63, p < 0.001), though not increased admission cost (OR: 1.01, p = 0.929). Our study identified HFRS to be significantly associated with prolonged hospitalizations and non-routine discharge. Other factors that were found to be associated with increased healthcare resource utilization include age, Hispanic race, West hospital region, large hospital size, and increasing number of AEs.

Junctional Kyphosis after Correction with Long Instrumentation for Late Posttraumatic Thoracolumbar Kyphosis: Characteristics and Risk Factors

Junctional kyphosis is a common complication after corrective long spinal fusion for adult spinal deformity. Whereas there is still a paucity of data on junctional kyphosis, specifically among late posttraumatic thoracolumbar kyphosis (LPTK) patients. Thus, the aim of this study was to investigate the characteristics and risk factors of junctional kyphosis in LPTK patients receiving long segmental instrumented fusion. We retrospectively reviewed a cohort of LPTK patients who had received long segmental instrumented fusion (>4 segments) in our center between January 2012 and January 2019. Radiographic assessments included the sagittal alignment, pelvic parameters, bone quality on CT images, and measurements of the cross-sectional area (CSA, cross-sectional area of muscle-vertebral body ratio × 100) and fat saturation fraction (FSF, cross-sectional area of fat-muscle body ratio × 100) of paraspinal muscles. Patients in this study were divided into those with junctional kyphosis or failure (Group J) and those without (Group NJ) during follow-up. Group J included patients with junctional kyphosis (Group JK) and patients with junctional failure (Group JF). A total of 65 patients (16 males and 49 females, average age 56.5 ± 23.4 years) were enrolled in this study. After (32.7 ± 8.5) months follow-up, 15 patients (23.1%) experienced junctional kyphosis, and four of them deteriorated into junctional failure. Eighty percent (12/15) of junctional kyphosis was identified within 6 months after surgery. In comparison with Group NJ, Group J were older (P=0.026), longer fusion levels (P < 0.001), greater thoracic kyphosis (P=0.01), greater global kyphosis (P=0.023), lower bone quality (P < 0.001), less CSA (P=0.005) and higher FSF (P <0.001) of paraspinal muscles. Preoperative global kyphosis more than 48.5° (P=0.001, odds ratio 1.793) and FSF more than 48.4 (P=0.010, odds ratio 2.916) were identified as independent risk factors of junctional kyphosis. Based on the statistical differences among Group NJ, Group JK and Group JF (P < 0.001), Group JF had lower bone quality than Group NJ (P < 0.001) and Group JK (P=0.015). In terms of patient-reported outcomes, patients in Group JF had worse outcomes in ODI and VAS scores, and PCS and MCS of SF-36 than Group NJ and group JK CONCLUSION: The prevalence of junctional kyphosis was 23.1% in LPTK patients after long segmental instrumented fusion. Preoperative hyperkyphosis and advanced fatty degeneration of paraspinal muscles were independent risk factors of junctional kyphosis. Patients with lower bone quality were more likely to develop junctional failure.

Accuracy and Feasibility of Bedrock Configuration Utilizing Mazor X Navigation System

<h3>Research Objectives</h3> To prove accuracy and feasibility of utilizing navigation for implantation of S2AI screws and triangular titanium rods in the bedrock configuration during open sacro-pelvic fixation in multilevel spinal fusion for adult spinal deformity. <h3>Design</h3> Retrospective chart review. <h3>Setting</h3> Single center, ambulatory care. <h3>Participants</h3> 18 adult multilevel spinal deformity patients. <h3>Interventions</h3> Reviewed consecutive cases where bilateral S2AI and TTRs were placed in an open approach from 10/2019-9/2020. Patients had preop CT scan for implant planning utilizing Mazor X. S2AI screws were planned into the caudal pelvic teardrop with TTRs placed 1cm proximal and cephalad. <h3>Main Outcome Measures</h3> Preop implant trajectory vs. postop implant placement. <h3>Results</h3> There was no significant difference for the caudal angle in the sagittal plane between pre- and post-operative TTRs and S2AI screws (31.33° ± 3.87° vs. 30.27° ± 3.40°, P = 0.24 and 39.34° ± 2.67° vs 39.32° ± 2.92°, P = 0.98, respectively). For the horizontal angle in the coronal plane there were no significant differences between the pre- and post-operative measurements for the TTRs placed on either the left or right side (38.44° ± 2.49° vs. 40.28° ± 2.88°, P = 0.09 and 40.03° ± 2.45° vs. 38.83° ± 1.85°, P = 0.23; respectively) or for the S2AI screws (36.92° ± 2.76° vs. 38.65° ± 3.19°, P = 0.15 and 39.06° ± 2.35° vs. 38.48° ± 2.24°, P = 0.62; respectively). There were no intraoperative complications and no implants had to be re-positioned. <h3>Conclusions</h3> Placing concomitant bilateral S2AI screws and TTRs in an open approach during multilevel deformity surgery is both feasible and accurate using the Mazor X navigation system. <h3>Author(s) Disclosures</h3> None.

Geriatric relationship with inpatient opioid consumption and hospital outcomes after open posterior spinal fusion for adult spine deformity

ObjectiveAs the population ages, increasing attention has been placed on identifying risk factors for poor surgical outcomes in the elderly. The aim of this study was to assess the impact of geriatric status on inpatient narcotic consumption and healthcare resource utilization in patients undergoing spinal fusion for adult spinal deformity. MethodsA retrospective study was performed using the Premier Healthcare Database (2016–2017). All adult patients who underwent thoracic/thoracolumbar fusion for spine deformity were identified using ICD-10-CM codes. Patients were categorized by age: 18–49 years-old (Young), 50–64 years-old (Older), and 65 + years-old (Geriatric). Patient demographics, comorbidities, hospital characteristics, intraoperative variables, adverse events (AEs), and healthcare resource utilization were assessed. Increased inpatient opioid use was categorized by MME (morphine milligram equivalents) admission consumption greater than the 75th percentile of the cohort. Multivariate logistic regression analysis was used to identify independent predictors of increased opioid usage, increased cost, and non-routine discharge (NRD). ResultsOf the 1831 patients identified, 199 (10.9 %) were in the Young cohort, 599 (32.7 %) were in the Older cohort, and 1033 (56.4 %) were in the Geriatric cohort. The Geriatric cohort had a greater proportion of patients who were Non-Hispanic White (p < 0.001) and government-insured (p < 0.001). Comorbidities [CCI (p < 0.001)] and frailty [mFI-5 (p < 0.001)] increased with age. AEs occurred at similar rates between cohorts. A greater proportion of Older patients consumed an increased amount of MMEs during their hospital stay (Young: 24.9 % vs. Older: 33.1 % vs. Geriatric: 20.2 %, p < 0.001). A greater proportion of Geriatric patients experienced high costs (p = 0.018), longer LOS (p = 0.011), and 30-day readmission (p = 0.004) compared to other cohorts. A significantly greater proportion of the Geriatric cohort experienced NRD (Young: 25.3 % vs. Older: 58.8 % vs. Geriatric: 83.0 %, p < 0.001) On multivariate analysis, Geriatric age was independently associated with NRD (OR: 11.59, p < 0.001), and inversely associated with increased MME use (OR: 0.66, p = 0.038). However, Older age was independently associated with increased MME use (OR: 1.58, p = 0.026) and NRD (OR: 4.27, p < 0.001), though not increased cost (OR: 1.49, p = 0.077). ConclusionOur study demonstrates that geriatric patients may require fewer opioids than younger patients but require greater resource utilization on discharge. Additional studies investigating the impact of aging are necessary to improve patient risk stratification, healthcare delivery, and patient outcomes.

Clinical impact of short limited lumbar fusion for adult spinal deformity with postural and radiological abnormalities

Extensive surgical spinopelvic fusion for patients with adult spinal deformity (ASD) to achieve optimal radiological parameters should be avoided. The aim of this study was to review clinical and imaging findings in patients with ASD with postural and radiological abnormalities who underwent a novel three-level limited lumbar fusion as two-stage surgery in an attempt to propose a better tolerated alternative to spinopelvic long fusion to the pelvis. The subjects were 26 patients with a minimum follow-up period of 2 years. Cobb angle, C7 sagittal vertical axis, and pelvic incidence (PI) minus lumbar lordosis (LL) were significantly improved after surgery and maintained at follow-up. Most radiological parameters were corrected with lateral interbody fusion (LIF) as the initial surgery, and few with posterior fusion. PI-LL remained high after limited lumbar fusion, but scores on patient-based questionnaires and sagittal and coronal tilt in gait analysis improved. In cases with postoperative progression of proximal junctional kyphosis (11.5%), residual L1–L2 local kyphosis after LIF was the most significant radiological feature. In some cases of ASD with postural abnormalities, short limited lumbar fusion gives sufficient postoperative clinical improvement with preservation of spinal mobility and activities of daily living. The range of fixation should be determined based on radiological parameters after LIF to avoid postoperative complications.

Impact of Affective Disorders on Inpatient Opioid Consumption and Hospital Outcomes Following Open Posterior Spinal Fusion for Adult Spine Deformity

Affective disorders (ADs) are common and have a profound impact on surgical recovery, though few have studied the impact of ADs on inpatient narcotic consumption. The aim of this study was to assess the impact of ADs on inpatient narcotic consumption and healthcare resource utilization in patients undergoing spinal fusion for adult spinal deformity. A retrospective cohort study was performed using the 2016-2017 Premier Healthcare Database. Adults who underwent adult spinal deformity surgery were identified using International Classification of Disease, Tenth Revision, codes. Patients were grouped based on comorbid diagnosis of an AD. Demographics, comorbidities, intraoperative variables, complications, length of stay, admission costs, and nonroutine discharge rates were assessed. Increased inpatient opioid use was categorized by morphine milligram equivalents consumption greater than the 75th percentile. Multivariate regression analysis was used to identify predictors of increased healthcare recourse utilization. Of the 1831 study patients, 674 (36.8%) had an AD. A smaller proportion of patients in the AD cohort were 65+ years of age (P= 0.001), while a greater proportion of patients in the AD cohort identified as non-Hispanic White (P < 0.001). A greater proportion of patients in the AD cohort had increased morphine milligram equivalents consumption (P < 0.001). The AD cohort also had a longer mean length of stay (P < 0.001). A greater proportion of patients in the AD cohort had nonroutine discharges (P= 0.039) and unplanned 30-day readmission (P= 0.041). On multivariate analysis, AD was significantly associated with increased cost (odds ratio: 1.61, P < 0.001) and nonroutine discharge (odds ratio: 1.36, P= 0.035). ADs may be associated with increased inpatient opioid consumption and healthcare resource utilization.

L5-S1 nonunion occurrence even after anterior column support combined with iliac screw fixation in long fusion for adult spinal deformity: CT-based analysis at 2-year follow-up.

Iliac screw fixation and anterior column support are highly recommended to prevent lumbosacral pseudarthrosis after long-level adult spinal deformity (ASD) surgery. Despite modern instrumentation techniques, a considerable number of patients still experience nonunion at the lumbosacral junction. However, most previous studies evaluating nonunion relied only on plain radiographs and only assessed when the implant failures occurred. Therefore, using CT, it is important to know the prevalence after iliac fixation and to evaluate risk factors for nonunion at L5-S1. Seventy-seven patients who underwent ≥ 4-level fusion to the sacrum using iliac screws for ASD and completed a 2-year postoperative CT scan were included in the present study. All L5-S1 segments were treated by interbody fusion. Lumbosacral fusion status was evaluated on 2-year postoperative CT scans using Brantigan, Steffee, and Fraser criteria. Risk factors for nonunion were analyzed using patient, surgical, and radiographic factors. The metal failure and its association with fusion status at L5-S1 were evaluated. Of the 77 patients, 12 (15.6%) showed nonunion at the lumbosacral junction on the 2-year CT scans. Multivariate analysis using logistic regression revealed that only higher American Society of Anesthesiologists (ASA) grade was a risk factor for nonunion (OR 25.6, 95% CI 3.196-205.048, p = 0.002). There were no radiographic parameters associated with fusion status at L5-S1. Lumbosacral junction rod fracture occurred more frequently in patients with nonunion than in patients with fusion (33.3% vs 6.2%, p = 0.038). Although iliac screw fixation and anterior column support have been performed to prevent lumbosacral nonunion during ASD surgery, 15.6% of patients still showed nonunion on 2-year postoperative CT scans. High ASA grade was a significant risk factor for nonunion. Rod fracture between L5 and S1 occurred more frequently in the nonunion group.

P125. Evaluating the impact of multiple sclerosis on 2-year postoperative outcomes following long fusion for adult spinal deformity: a propensity score matched analysis

<h3>BACKGROUND CONTEXT</h3> The impact of neuromuscular disorders such as multiple sclerosis (MS) on outcomes following long segment (4+ level) fusion is underreported. <h3>PURPOSE</h3> To identify the impact of MS on two-year (2Y) postoperative complications and revisions following 4 level fusion for ASD. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort. <h3>PATIENT SAMPLE</h3> Patients undergoing 4+ level fusion for ASD were identified from the New York State Statewide Planning and Research Cooperative System. <h3>OUTCOME MEASURES</h3> Two-year postoperative complications and reoperations. <h3>METHODS</h3> Patients undergoing 4-level fusion for ASD were identified from the New York Statewide Planning and Research Cooperative System. Patients with a baseline diagnosis of MS were also identified. Patients with infectious/traumatic/neoplastic indications were excluded. Subjects were 1:1 propensity score-matched (MS to no-MS) by age, sex, and race and compared for rates of 2-year postoperative complications and reoperations. Logistic regression models were utilized to determine risk factors for adverse outcomes at 2 years. <h3>RESULTS</h3> A total of 86 patients were included (n=43 per group). Age (50.1 vs 50.1 years, p=0.225), sex and race were comparable between groups. MS pts incurred higher charges for their surgical visit ($125,906 vs $84,006, p=0.007) with similar LOS (8.1 vs 5.3 days, p>0.05). MS patients experienced comparable rates of overall medical complications (30.1% vs 25.6%) and surgical complications (34.9% vs 30.2%) all p>0.05. MS pts had similar rates of 2-year revisions (16.3% vs 9.3%, p=0.333). MS was not associated with medical, surgical or overall complications or revisions at minimum 2-year follow-up. <h3>CONCLUSIONS</h3> Patients with MS experienced similar postoperative course compared to those without MS following 4-level fusion for ASD. This data supports the findings of multiple previously published case series' that long segment fusions for ASD can be performed relatively safely in patients with MS. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

54. PMMA augmentation is not protective against proximal junctional kyphosis in adult spinal deformity correction bridging the thoracolumbar junction

<h3>BACKGROUND CONTEXT</h3> Proximal junctional kyphosis (PJK) is a relatively common complication following adult spinal deformity surgery. Some studies have demonstrated cement augmentation of the upper instrumented vertebra (UIV) decreases development of acute PJK, while others have been inconclusive. This study quantifies the radiographic progression of PJK in patients undergoing instrumented spinal fusion for adult deformity crossing the thoracolumbar junction with and without polymethylmethacrylate (PMMA) vertebroplasty. <h3>PURPOSE</h3> Determine whether polymethylmethacrylate (PMMA) vertebroplasty is protective against development of proximal junctional kyphosis. <h3>STUDY DESIGN/SETTING</h3> Single center, retrospective. <h3>PATIENT SAMPLE</h3> One hundred patients who underwent thoracolumbar fusion between 2013 and 2020. <h3>OUTCOME MEASURES</h3> Development of proximal junctional kyphosis at 6 weeks, 6 months, 12 months and 24 months postoperative. <h3>METHODS</h3> A retrospective cohort of 100 patients who underwent thoracolumbar fusion between 2013 and 2020 was identified. PMMA augmentation at the UIV and UIV+1 was performed at the discretion of the treating surgeon. Degree of PJK was measured from preoperative scoliosis, immediate postoperative, 6-week, 6-month, 12-month, and 24-month radiographs. Osteoporosis and osteopenia were defined as a DEXA T score ≤ -2.5 and ≤ -1, respectively. Differences in PJK and reoperation rates between PMMA and non-PMMA groups were assessed with stratified Kaplan-Meier survival curves and 95% confidence intervals with log-rank tests. Other categorical variables were assessed with chi-square and Fisher's exact tests while continuous variables were assessed with Mann Whitney U tests. Bonferroni correction was used to adjust the error rate for the multiple time points when appropriate. Multivariable Cox proportional hazard models adjusted for osteoporosis, degenerative disc disease, number of levels fused, pain medications taken, osteoporosis medications taken, age, sex and PI-LL mismatch > ± 9. All analyses were performed with SAS vs 9.4 with a two-sided level of significance of α = 0.05. <h3>RESULTS</h3> One hundred patients were included. The median age was 68 (interquartile range (IQR) 64-73) and median follow up was 43 months (IQR 34 - 54). Of the cohort, 56% received PMMA, and this group was significantly older (p=0.021), more often female (p=0.04), and had a higher rate of osteopenia (p < 0.01) and osteoporosis (p=0.038), took more preoperative pain medications (p=0.02), and more often underwent concurrent decompression (p < 0.01). Patients augmented with PMMA had significantly lower DEXA scores (p=0.024). Of PMMA patients, 55.4% developed PJK compared to 44.6% of Non-PMMA patients (p=0.097). Patients augmented with PMMA had higher rates of PJK at 6 months, but there was no difference at any further time point. The rate of all cause reoperation was 7.1% in the PMMA group compared to 11.4% in the Non-PMMA group (p=0.501). In multivariable models, PJK risk was significantly predicted by the presence of osteopenia (p=0.002) and presence of osteoporosis (p < 0.03). After risk adjustment, there was no difference in PJK rates attributable to PMMA use (HR 0.77, 95% CI 0.38-1.6, p = 0.47). <h3>CONCLUSIONS</h3> In long thoracolumbar fusions for adult spinal deformity, PMMA augmentation was not protective against PJK. Osteopenia and osteoporosis were significantly associated with higher rates of PJK. This suggests a complex interplay of surgical, biomechanical and patient factors in achieving an optimal outcome. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Factors Affecting Stiffness-Related Functional Disability After Long Segmental Fusion for Adult Spinal Deformity.

In general, stiffness-related functional disability (SRFD) is expected to increase as longer fusion length, but there have been no studies on factors affecting SRFD besides fusion length. To identify the factors affecting SRFD after long segmental fusion in patients with adult spinal deformity (ASD). We retrospectively reviewed the patients who underwent ≥4-segment fusion including sacrum for ASD. The severity of SRFD was evaluated using the Specific Functional Disability Index (SFDI) consisting of 12 items with 4 categories as follows: sitting on the floor, sanitation activity, lower body activity, and moving activity. Each category contains 3 items which was given a maximum of 4 points. The presumed factors affecting SFDI were analyzed. A total of 148 patients were included in the study with their mean age of 67.3 years. The mean fusion length was 6.4 segments. The mean score of each SFDI category was highest in sitting on the floor (9.9), followed by lower body activities (7.6), sanitation activities (6.0), and moving activities (5.9). The total sum was 29.3 points. In multivariate analysis, total sum of SFDI was significantly higher in female sex, patients with higher American Society of Anesthesiology grade, and longer fusion length. However, the sagittal parameters did not show a significant correlation with SRFD, except pelvic incidence-lumbar lordosis which correlated with only one category (lower body activities). This study showed that female sex, higher American Society of Anesthesiology grades, and longer fusion length influenced SRFD after long segmental fusion for ASD. Sagittal parameters related to the degree of deformity correction did not significantly affect SRFD.

Analysis of Mechanical Failure Using the GAP Score After Surgery With Lateral and Posterior Fusion for Adult Spinal Deformity.

A retrospective observational study. The purpose of this study was to evaluate the Global Alignment and Proportion (GAP) score and mechanical failure (MF) following corrective fusion surgery with planned 2-stage surgery using lateral lumbar interbody fusion in patients with adult spinal deformity (ASD). Fifty-four patients (2 men, 52 females, aged 70.3years) were included. MF, proximal junctional failure (PJF), and rod breakage (RB) occurred in 46.3% (25/54), 22.2% (12/54), and 29.6% (16/54) of patients, respectively. The immediate postoperative GAP scores were compared between patients with MF and without MF (MF+ and MF-, respectively). GAP scores in groups with and without PJF or RB were also compared. Patients were grouped according to the GAP score for spinopelvic alignment: 23 (42.6%) as proportioned, 22 (40.7%) as moderately disproportioned, and 9 (16.7%) as severely disproportioned. The pre- and postoperative spinopelvic parameters did not differ significantly between the MF- and MF+ groups except pelvic incidence. Postoperatively, the mean pelvic incidence-lumbar lordosis changed to <10° in both groups. The GAP score and 3 categories of GAP scores did not differ significantly between the PJF- and PJF+ groups or between the RB+ and RB- groups. Multiple factors can cause PJF and RB, and the patient's background may affect the ability to use the GAP score to predict MF. Further research may be needed in the future using modified GAP scores with additional factors in ASD patients.

111 Comparison of Hounsfield Units Versus T-Score in Predicting Postoperative Proximal Junctional Kyphosis

INTRODUCTION: Vertebral body (VB) bone quality is generally estimated indirectly via femoral neck dual-energy x-ray absorptiometry (DEXA) to counsel patients on their risk for development of proximal junctional kyphosis (PJK) after thoraco-lumbar fusion for adult spinal deformity. It is currently unknown whether direct measurement of VB bone quality through Hounsfield unit analysis (HUs) can successfully stratify patients on their risk of delayed complications. METHODS: 108 patients who underwent surgery for ASD were enrolled. Demographic characteristics, radiologic measurements, complication profile, and clinical outcomes were recorded both pre- and post-operatively. A Youden J-statistic was calculated based on an ROC analysis of the UIV Hounsfield unit data to give a single HU threshold to segregate patients into either a high or low HU group. Patient groups were then compared with respect to the mentioned clinical and radiographic outcome measures. RESULTS: Youden statistic revealed a HU threshold value of 126.8 for maximal group stratification. Significant change in proximal junctional cobb angle (PJCA) was observed between the low and high HU groups at one and two years (p &lt; 0.0001 and p = 0.0001 respectively). This was not similarly seen in hip or spine DEXA analysis (p &gt; 0.05). CONCLUSION: Assessment of bone quality via pre-operative measurement of the UIV VB HU can predict post-operative changes in PJCA. UIV HUs &lt; 126.8 are associated with 2.8x elevated risk of developing post-operative PJK. Current standard of care measurement of bone quality via femoral neck DEXA is of more limited utility compared to HU analysis.

Comparison of Hybrid Posterior Fixation and Conventional Open Posterior Fixation Combined with Multilevel Lateral Lumbar Interbody Fusion for Adult Spinal Deformity.

We compared radiological and clinical outcomes between multilevel lateral lumbar interbody fusion (LLIF) + hybrid posterior fixation (PF) and multilevel LLIF + conventional open PF in patients with adult spinal deformity (ASD). Patients who underwent minimally invasive surgery for ASD in a single institution between 2014 and 2018 were retrospectively reviewed. Fifty-six patients (hybrid PF, 30; open PF, 26) who underwent ASD correction surgery were enrolled between 2014 and 2018. We evaluated patients’ demographics, clinical outcomes, and radiographical parameters in each group. There was significantly less estimated blood loss in the hybrid PF group (662.8 mL vs. 1088.8 mL; p = 0.012). The CRP level 7 days after surgery was significantly lower in the hybrid PF group (2.9 mg/dL vs. 4.3 mg/dL; p = 0.035). There was no significant difference between the two groups in other demographic variables, visual analog scores for back pain and leg pain, Oswestry Disability Index, coronal Cobb angle, lumbar lordosis, pelvic tilt, pelvic incidence–lumbar lordosis mismatch, and sagittal vertical axis. There was a significantly higher percentage of major complications in the open PF group (42.3% vs. 13.3%; p = 0.039). Thus, LLIF + hybrid PF for ASD corrective surgery may be comparable to LLIF + open PF in terms of clinical and radiographic outcomes.

Circumferential Bone Fusion in Adult Spinal Deformity via Combination of Oblique Lateral Interbody Fusion and Grade 2 Posterior Column Osteotomy.

Retrospective study. The combination of oblique lateral interbody fusion (OLIF) with grade 2 posterior column osteotomy (PCO) is an effective treatment for adult spinal deformity. However, grade 2 PCO may lead to pseudoarthrosis because it involves complete removal of the bilateral posterior facet joints. The main study objective was to determine the achievement rate of anterior and posterolateral fusion resulting in circumferential fusion in patients who underwent combined OLIF and grade 2 PCO. This retrospective study included consecutive patients who underwent OLIF and grade 2 PCO. The group comprised a long fusion group, with fusion from the thoracic level to the ilium, and a short fusion group, with fusion within the lumbar region. The OLIF with percutaneous pedicle screw insertion group was also used for reference. The Brantigan-Steffee-Fraser classification was used to assess interbody fusion and Lenke classification for assessment of posterolateral fusion. Sixty-six patients with 109 lumbar levels were included in the study. We observed 100% anterior fusion in all 3 groups. The fusion rate for posterolateral fusion between the OLIF-grade 2 PCO group was 97%, with very low (3%) non-circumferential fusion (pseudoarthrosis only at the osteotomy site). In most cases, solid posterolateral fusions (Lenke A) occurred within 24 months. The combination of OLIF and grade 2 PCO resulted in circumferential fusion for most (97%) of the cases within 24 months. OLIF and grade 2 PCO are considered a good combination treatment to achieve sufficient lumbar lordosis and solid bone fusion.

Hidden blood loss in extreme lateral interbody fusion for adult spinal deformity

BackgroundExtreme lateral interbody fusion (XLIF) is often used with posterior spinal fixation (PSF) to treat adult spinal deformity (ASD). However, the amount of intraoperative blood loss (IBL) reported for XLIF may underestimate the total blood loss (TBL). The objective of this study was to determine the total perioperative blood loss in XLIF for ASD. MethodsWe assessed 30 consecutive ASD patients with Schwab-SRS type L (mean age: 68.7 ± 8.2 years; mean follow-up 2.0 ± 1.3 years) who were treated by multilevel XLIF (mean, 2.5 ± 0.6 levels) followed by PSF after 3–5 days. We calculated the TBL after XLIF by the Gross equation, by hemoglobin (Hb) balance, and by the Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) formula. We defined hidden blood loss (HBL) as the difference between the TBL and IBL. Pearson correlation, Spearman correlation, and multiple logistic regression analysis were performed to investigate the risk factors related to HBL. ResultsPost-XLIF blood tests showed a significant decrease in the Hb (from 11.8 ± 1.1 mg/dl to 10.6 ± 1.1 mg/dl) and hematocrit (from 36.0 ± 3.2% to 32.5 ± 3.2%). Although the mean IBL was relatively small (33 ± 52 mL), we calculated the TBL as 291 ± 171 mL (Gross equation) and the HBL as 258 ± 168 mL by Gross equation, which was 8 times greater than the IBL on average. There was no difference in the results obtained using the three methods. Multiple logistic regression analysis indicated preoperative lumber lordosis was the risk factor of high HBL (Odds ratio = 1.085, 95%CI: 1.006–1.170, p = 0.035). ConclusionsThe HBL in XLIF was 8 times greater than the IBL. During the perioperative course of correction and fusion surgery for ASD with XLIF, surgeons need to pay attention not to underestimate the TBL.

CORR Insights®: Are the Choice of Frame and Intraoperative Patient Positioning Associated With Radiologic and Clinical Outcomes in Long-instrumented Lumbar Fusion for Adult Spinal Deformity?

CORR Insights®: Are the Choice of Frame and Intraoperative Patient Positioning Associated With Radiologic and Clinical Outcomes in Long-instrumented Lumbar Fusion for Adult Spinal Deformity?

Utility of the MISDEF2 Algorithm and Extent of Fusion in Open Adult Spinal Deformity Surgery With Minimum 2-Year Follow-up.

ObjectiveLong-segment fusion in adult spinal deformity (ASD) is often needed, but more focal surgeries may provide significant relief with less morbidity. The minimally invasive spinal deformity surgery (MISDEF2) algorithm guides minimally invasive ASD surgery, but it may be useful in open ASD surgery. We classified ASD patients undergoing focal decompression, limited decompression and fusion, and full correction according to MISDEF2 and correlated outcomes. MethodsA retrospective study of ASD patients treated by 2 surgeons at our hospital was performed. Inclusion criteria were: age > 50, minimum 2-year follow-up, and open ASD surgery. Tumor, trauma, and infections were excluded. Patients had open surgery including focal decompression, short segment fusion, or full scoliosis correction. All patients were categorized by MISDEF2 into 4 classes based upon spinopelvic parameters. Perioperative metrics were assessed. Radiographic correction, complications and reoperation were recorded. ResultsA total of 136 patients met inclusion criteria. Mean follow-up was 46±15.8 months (range, 24–118 months). Forty-seven underwent full deformity correction, 71 underwent short segment fusion, and 18 underwent decompression alone. There were 24 cases of class I, 66 cases of class II, 23 cases of class III, and 23 cases of class IV patients. Patients in class I and II had perioperative complication rates of 0% and 16.7% and revision rates of 8% and 21.2% when undergoing focal decompression or limited fusion. However, class II patients undergoing full correction had higher perioperative complications rate (p=0.03) and revision surgery rates (p=0.047). This difference was not seen in class III patients (p>0.05). All class IV patients underwent full correction, but they had higher perioperative complication rates (p<0.019), comparable revision surgery rates (p=0.27), and better radiographic realignment (p<0.001). In addition, full deformity correction was associated with longer length of stay, increased blood loss, and longer operative time (p<0.001). ConclusionThe MISDEF2 algorithm may help guide ASD surgical decision making even in open surgery, with focal treatment used in class I and II patients as a viable alternative and full correction implemented in class IV patients because of severe malalignment. However, class II patients with ASD undergoing full deformity correction do have higher complication rates.

Pelvic incidence is a risk factor for lower instrumented vertebra failure in adult spinal deformity patients who underwent corrective fusion terminating at the L5 vertebra

BackgroundFactors related to postoperative mechanical failure after long fusion with lower instrumented vertebra (LIV) at L5 have not been well investigated. Elucidating such factors may allow us to perform alternatives to spinopelvic fusion for adult spinal deformity (ASD) cases. We investigated the incidence and risk factors of LIV failure in patients with ASD who underwent surgical treatment of long corrective fusion until the L5 vertebrae. MethodsBetween 2009 and 2018, 52 patients who underwent corrective fusions to L5 were followed-up for at least one-year. We evaluated the associated patient factors for LIV failure which include loosening of the pedicle screw of LIV, fracture of LIV, distal junctional kyphosis (DJK). ResultsThe mean age of the participants was 71.2 ± 7.59 (range, 44–84). LIV failure occurred in 20 patients (38.5%), and 6 patients (11.5%) underwent secondary surgery for caudal segments. The mean pelvic incidence (PI) was 52.5 ± 9.8 in the failure group versus 45.3 ± 11.4 in non-failure group (P = 0.02) and pelvic tilt (PT) was 39.1 ± 9.0 versus 32.4 ± 13.0. There were no significant differences in sex, age, body mass index, number of levels fused, and other radiographic data. Logistic regression analysis that included T1 pelvic angle, PT, PI - postoperative LL and PI also identified PI as the only significant determinant of LIV failure (OR = 1.07, P = 0.034). Receiver operating characteristic analysis demonstrated that a PI over 50.0° was associated with LIV failure (sensitivity 63%, specificity 70%, AUC 0.694). ConclusionLIV failure was frequently observed after long corrective fusion for patients with ASD. High PI was found to be a significant risk factor for the LIV failure.

Are the Choice of Frame and Intraoperative Patient Positioning Associated With Radiologic and Clinical Outcomes in Long-instrumented Lumbar Fusion for Adult Spinal Deformity?

Previous studies of patient positioning during spinal surgery evaluated intraoperative or immediate postoperative outcomes after short-instrumented lumbar fusion. However, patient positioning during long-instrumented fusion for an adult spinal deformity (ASD) might be associated with differences in intraoperative parameters such as blood loss and longer-term outcomes such as spine alignment, and comparing types of surgical tables in the context of these larger procedures and evaluating longer-term outcome scores seem important. (1) Do blood loss and the number of transfusions differ between patients who underwent multi-level spinal fusion with a Wilson frame and those with a four-poster frame? (2) Does restoration of lumbar lordosis and the sagittal vertical axis differ between patients who underwent surgery with the use of one frame or the other? (3) Do clinical outcomes as determined by Numeric Rating Scale and Oswestry Disability Index scores differ between the two groups of patients? (4) Are there differences in postoperative complications between the two groups? Among 651 patients undergoing thoracolumbar instrumented fusion between 2015 and 2018, 129 patients treated with more than four levels of initial fusion for an ASD were identified. A total of 48% (62 of 129) were eligible; 44% (57 of 129) were excluded because of a history of fusion, three-column osteotomy, or surgical indications other than degenerative deformity, and another 8% (10 of 129) were lost before the minimum 2-year follow-up period. Before January 2017, one surgeon in this study used only a Wilson frame; starting in January 2017, the same surgeon consistently used a four-poster frame. Forty patients had spinal fusion using the Wilson frame; 85% (34 of 40) of these had follow-up at least 2 years postoperatively (mean 44 ± 13 months). Thirty-two patients underwent surgery using the four-poster frame; 88% (28 of 32) of these were available for follow-up at least 2 years later (mean 34 ± 6 months). The groups did not differ in terms of age, gender, BMI, type of deformity, or number of fused levels. Surgical parameters such as blood loss and the total amount of blood transfused were compared between the two groups. Estimated blood loss was measured by the amount of suction drainage and the amount of blood that soaked gauze. The decision to transfuse blood was based on intraoperative hemoglobin values, a protocol that was applied equally to both groups. Radiologic outcomes including sagittal parameters and clinical outcomes such as the Numerical Rating Scale score for back pain (range 0-10; minimal clinically important difference [MCID] 2.9) and leg pain (range 0-10; MCID 2.9) as well as the Oswestry Disability Index score (range 0-100; MCID 15.4) were also assessed through a longitudinally maintained database by two spine surgeons who participated in this study. Repeated-measures analysis of variance was used to compare selected radiologic outcomes between the two groups over time. Blood loss and the total amount of transfused blood were greater in the Wilson frame group than in the four-poster frame group (2019 ± 1213 mL versus 1171 ± 875 mL; mean difference 848 [95% CI 297 to 1399]; p = 0.003 for blood loss; 1706 ± 1003 mL versus 911 ± 651 mL; mean difference 795 [95% CI 353 to 1237]; p = 0.001 for transfusion). Lumbar lordosis and the sagittal vertical axis were less restored in the Wilson frame group than in the four-poster frame group (7° ± 10° versus 18° ± 14°; mean difference -11° [95% -17° to -5°]; p < 0.001 for lumbar lordosis; -22 ± 31 mm versus -43 ± 27 mm; mean difference 21 [95% CI 5 to 36]; p = 0.009 for the sagittal vertical axis). Such differences persisted at 2 years of follow-up. The proportion of patients with the desired correction was also greater in the four-poster frame group than in the Wilson frame group immediately postoperatively and at 2 years of follow-up (50% versus 21%, respectively; odds ratio 3.9 [95% CI 1.3 to 11.7]; p = 0.02; 43% versus 12%, respectively; odds ratio 5.6 [95% CI 1.6 to 20.3]; p = 0.005). We found no clinically important differences in postoperative patient-reported outcomes including Numeric Rating Scale and Oswestry Disability Index scores, and there were no differences in postoperative complications at 2 years of follow-up. The ideal patient position during surgery for an ASD should decrease intra-abdominal pressure and induce lordosis as the abdomen hangs freely and hip flexion is decreased. The four-poster frame appears advantageous for long-segment fusions for spinal deformities. Future studies are needed to extend our analyses to different types of spinal deformities and validate radiologic and clinical outcomes with follow-up for more than 2 years. III, therapeutic study.

Prevalence and location of endplate fracture and subsidence after oblique lumbar interbody fusion for adult spinal deformity

BackgroundRecently, Oblique lumbar interbody fusion (OLIF) is commonly indicated to correct the sagittal and coronal alignment in adult spinal deformity (ASD). Endplate fracture during surgery is a major complication of OLIF, but the detailed location of fracture in vertebral endplate in ASD has not yet been determined. We sought to determine the incidence and location of endplate fracture and subsidence of the OLIF cage in ASD surgery, and its association with fusion status and alignment.MethodsWe analyzed 75 levels in 27 patients were analyzed using multiplanar CT to detect the endplate fracture immediately after surgery and subsidence at 1 year postoperatively. The prevalence was compared between anterior and posterior, approach and non-approach sides, and concave and convex side. Their association with fusion status, local and global alignment, and complication was also investigated.ResultsEndplate fracture was observed in 64 levels (85.3%) in all 27 patients, and the incidence was significantly higher in the posterior area compared with the anterior area (85.3 vs. 68.0%, p=0.02) of affected vertebra in the sagittal plane. In the coronal plane, there was no significant difference in incidence between left (approach) and right (non-approach) sides (77.3 and 81.3%, respectively), or concave and convex sides (69.4 and 79.6%) of wedged vertebra. By contrast, cage subsidence at 1 year postoperatively was noted in 14/75 levels (18.7%), but was not associated with endplate fracture. Fusion status, local and global alignment, and complications were not associated with endplate fracture or subsidence.ConclusionEndplate fracture during OLIF procedure in ASD cases is barely avoidable, possibly induced by the corrective maneuver with ideal rod counter and cantilever force, but is less associated with subsequent cage subsidence, fusion status, and sustainment of corrected alignment in long fusion surgery performed even for elderly patients.