Treatment of adult thoracolumbar spinal deformity: past, present, and future

Have We Made Advancements in Optimizing Surgical Outcomes and Enhancing Recovery for Patients With High-Risk Adult Spinal Deformity Over Time?

BACKGROUND AND OBJECTIVES

The spectrum of patients requiring adult spinal deformity (ASD) surgery is highly variable in baseline (BL) risk such as age, frailty, and deformity severity. Although improvements have been realized in ASD surgery over the past decade, it is unknown whether these carry over to high-risk patients. We aim to determine temporal differences in outcomes at 2 years after ASD surgery in patients stratified by BL risk.

METHODS

Patients ≥18 years with complete pre- (BL) and 2-year (2Y) postoperative data from 2009 to 2018 were categorized as having undergone surgery from 2009 to 2013 [early] or from 2014 to 2018 [late]. High-risk [HR] patients met ≥2 of the criteria: (1) ++ BL pelvic incidence and lumbar lordosis or SVA by Scoliosis Research Society (SRS)-Schwab criteria, (2) elderly [≥70 years], (3) severe BL frailty, (4) high Charlson comorbidity index, (5) undergoing 3-column osteotomy, and (6) fusion of >12 levels, or >7 levels for elderly patients. Demographics, clinical outcomes, radiographic alignment targets, and complication rates were assessed by time period for high-risk patients.

RESULTS

Of the 725 patients included, 52% (n = 377) were identified as HR. 47% (n = 338) had surgery pre-2014 [early], and 53% (n = 387) underwent surgery in 2014 or later [late]. There was a higher proportion of HR patients in Late group (56% vs 48%). Analysis by early/late status showed no significant differences in achieving improved radiographic alignment by SRS-Schwab, age-adjusted alignment goals, or global alignment and proportion proportionality by 2Y (all P > .05). Late/HR patients had significantly less poor clinical outcomes per SRS and Oswestry Disability Index (both P < .01). Late/HR patients had fewer complications (63% vs 74%, P = .025), reoperations (17% vs 30%, P = .002), and surgical infections (0.9% vs 4.3%, P = .031). Late/HR patients had lower rates of early proximal junctional kyphosis (10% vs 17%, P = .041) and proximal junctional failure (11% vs 22%, P = .003).

CONCLUSION

Despite operating on more high-risk patients between 2014 and 2018, surgeons effectively reduced rates of complications, mechanical failures, and reoperations, while simultaneously improving health-related quality of life.

Predictive factors for osteoporosis in adult spinal deformity patients

PURPOSE

This study aimed to identify predictive factors for femoral bone mineral density (BMD) in adult patients with spinal deformity and to establish cutoff values for detecting osteoporosis using preoperative computed tomography (CT) scans.

METHODS

A retrospective analysis was conducted on 90 patients with adult spinal deformity (ASD) who underwent preoperative bone density testing. Key parameters such as age, body mass index (BMI), and Hounsfield unit (HU) values from various vertebral levels were analyzed. Dual-energy X-ray absorptiometry (DXA) was used to measure BMD T-score, and HU values were measured at C2, C7, T8, T9, L1, L2, and L3.

RESULTS

Multivariate regression analyses identified BMI and HU at C2 as independent predictors of femoral T-score. The following predictive equation was developed: femoral T-score = - 5.178 + 0.053 × BMI + 0.006 × C2 HU (R2 = 0.50). The formula derived from these variables explained 50% of the variance in femoral T-score. Receiver operating characteristic analysis identified cutoff values for predicting osteoporosis as 281 for C2 HU and 22.9 for BMI. The areas under the curve were 0.751 and 0.638, respectively.

CONCLUSION

These findings suggest that HU values from preoperative CT scans can serve as reliable indicators of femoral T-score, offering an alternative to DXA in cases where DXA is unavailable or inaccurate due to factors like severe spinal degeneration. This approach could enhance the preoperative assessment of osteoporosis in ASD patients by facilitating more targeted use of DXA and improving overall clinical decision-making.

LEVEL OF EVIDENCE

IV.

Topping-Off a Long Thoracic Stabilization With Semi-Rigid Constructs May Have Favorable Biomechanical Effects to Prevent Proximal Junctional Kyphosis: A Biomechanical Comparison

Study DesignIn-vitro cadaveric biomechanical study.ObjectivesLong posterior spinal fusion is a standard treatment for adult spinal deformity. However, these rigid constructs are known to alter motion and stress to the adjacent non-instrumented vertebrae, increasing the risk of proximal junctional kyphosis (PJK). This study aimed to biomechanically compare a standard rigid construct vs constructs "topped off" with a semi-rigid construct. By understanding semi-rigid constructs' effect on motion and overall construct stiffness, surgeons and researchers could better optimize fusion constructs to potentially decrease the risk of PJK and the need for revision surgery.MethodsNine human cadaveric spines (T1-T12) underwent non-destructive biomechanical range of motion tests in pure bending or torsion and were instrumented with an all-pedicle-screw (APS) construct from T6-T9. The specimens were sequentially instrumented with semi-rigid constructs at T5: (i) APS plus sublaminar bands; (ii) APS plus supralaminar hooks; (iii) APS plus transverse process hooks; and (iv) APS plus short pedicle screws.ResultsAPS plus transverse process hooks had a range of motion (ie, relative angle) for T4-T5 and T5-T6, as well as an overall mechanical stiffness for T1-T12, that was more favourable, as it reduced motion at adjacent levels without a stark increase in stiffness. Moreover, APS plus transverse process hooks had the most linear change for range of motion across the entire T3-T7 range.ConclusionsPresent findings suggest that APS plus transverse process hooks has a favourable biomechanical effect that may reduce PJK for long spinal fusions compared to the other constructs examined.

Adult Cervical Deformity Patients Have Higher Baseline Frailty, Disability, and Comorbidities Compared With Complex Adult Thoracolumbar Deformity Patients: A Comparative Cohort Study of 616 Patients

STUDY DESIGN

Multicenter comparative cohort.

OBJECTIVE

Studies have shown markedly higher rates of complications and all-cause mortality following surgery for adult cervical deformity (ACD) compared with adult thoracolumbar deformity (ATLD), though the reasons for these differences remain unclear. Our objectives were to compare baseline frailty, disability, and comorbidities between ACD and complex ATLD patients undergoing surgery.

METHODS

Two multicenter prospective adult spinal deformity registries were queried, one ATLD and one ACD. Baseline clinical and frailty measures were compared between the cohorts.

RESULTS

616 patients were identified (107 ACD and 509 ATLD). These groups had similar mean age (64.6 vs 60.8 years, respectively, P = .07). ACD patients were less likely to be women (51.9% vs 69.5%, P < .001) and had greater Charlson Comorbidity Index (1.5 vs .9, P < .001) and ASA grade (2.7 vs 2.4, P < .001). ACD patients had worse VR-12 Physical Component Score (PCS, 25.7 vs 29.9, P < .001) and PROMIS Physical Function Score (33.3 vs 35.3, P = .031). All frailty measures were significantly worse for ACD patients, including hand dynamometer (44.6 vs 55.6 lbs, P < .001), CSHA Clinical Frailty Score (CFS, 4.0 vs 3.2, P < .001), and Edmonton Frailty Scale (EFS, 5.15 vs 3.21, P < .001). Greater proportions of ACD patients were frail (22.9% vs 5.7%) or vulnerable (15.6% vs 10.9%) based on EFS (P < .001).

CONCLUSIONS

Compared with ATLD patients, ACD patients had worse baseline characteristics on all measures assessed (comorbidities/disability/frailty). These differences may help account for greater risk of complications and all-cause mortality previously observed in ACD patients and facilitate strategies for better preoperative optimization.

Long-term reoperation risk of thoracic to pelvis instrumentation for spinal deformity: a longitudinal study of 7,062 patients

PURPOSE

To perform a large-scale assessment of reoperation risk among spine deformity patients undergoing thoracic to pelvis surgery.

METHODS

The PearlDiver database was queried for spinal deformity patients (scoliosis, kyphosis, spondylolisthesis, sagittal plane deformity) undergoing at minimum, a T12-pelvis operation (2010-2020). CPT codes identified lumbar arthrodesis procedures that included pelvic fixation and ≥ 7 levels of posterior instrumentation on the same day. Minimum follow-up was 2 years. Reoperations included subsequent arthrodesis, decompression, osteotomy, device insertion, and pelvic fixation procedures. Multivariable regression analysis described associations between variables and reoperation risk.

RESULTS

7,062 patients met criteria. Overall reoperation rate was 23.2%. Reoperation rate at 2- and 5-year was 16.9% and 22.1% respectively. 10-year reoperation-free probability was 73.7% (95% CI: 72.4-74.9%). Multivariable analysis revealed higher reoperation risk for patients with kyphosis and ≥ 13 levels of posterior instrumentation. Patients who received interbody cages had a lower reoperation risk. No association was found between the presence or absence of osteotomy procedures and reoperation risk. Lastly, linear regression analyses revealed no significant relationship between age or ECI and risk for subsequent operations did not independently influence reoperation.

CONCLUSIONS

This study, representing a real-world cohort of over six times the largest current prospective data set, found a 2-year reoperation rate of 17%, similar to previous studies, suggesting study group findings are applicable to a broader population. Preoperative kyphosis and ≥ 13 levels of posterior instrumentation was associated with higher reoperation risk, while the use of interbody cages was protective. Age, medical comorbidities, and osteotomies did not predict reoperations.

Rod Contour Angle and Postoperative Thoracic Kyphosis: Key Predictors of Proximal Junctional Kyphosis in Pediatric Neuromuscular Scoliosis after Spinopelvic Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Proximal junctional kyphosis (PJK) is a postoperative complication in spinal deformity surgery causing pain, functional deterioration, and potential revision surgery, with challenges in the neuromuscular scoliosis (NMS) population. We investigated the incidence, risk factors, and clinical impact of PJK in nonambulatory pediatric NMS patients following spinopelvic fusion.

METHODS

Seventy-two NMS patients who underwent spinopelvic fusion from the upper thoracic vertebra to the pelvis were reviewed, with a minimum 2-year follow-up. Radiographic measurements and clinical data were analyzed to identify PJK predictors and evaluate outcomes. PJK was defined as a proximal junctional angle (PJA) ≥10° and an increase of ≥10° from preoperative measurements. Statistical analyses included t-tests, ROC curve analysis, logistic regression, and linear regression.

RESULTS

The incidence of PJK was 25%. Significant predictors included rod contour angle (RCA) (odds ratio [OR]: 1.11, P = 0.04), postoperative T2-T12 kyphosis (OR: 1.04, P = 0.043), and the difference between postoperative T2-T12 kyphosis and RCA (OR: 1.04, P = 0.021). A bidirectional relationship between pre- and postoperative PJA was observed. Lower preoperative PJA was associated with an increased risk of PJK (area under the curve [AUC]: 0.78, P < 0.001). Conversely, high preoperative PJA tended to decrease after surgery. No revision surgeries were performed for PJK.

CONCLUSION

This study reveals a 25% incidence of PJK in NMS patients undergoing spinopelvic fusion. Preoperative radiographic evaluation warrants particular attention in cases exhibiting decreased PJA values. Furthermore, meticulous intraoperative optimization of PJA, RCA, and thoracic kyphosis appears crucial for minimizing PJK occurrence.

Long-term follow-up of non‑neurologic and neurologic complications after complex adult spinal deformity surgery: results from the Scoli-RISK-1 study

PURPOSE

To report all complications that occurred during the 2 to 5-year postoperative period, describe reoperations during this time period, and compare patients who did and did not have major, surgery-related complications and/or reoperations during this time period.

METHODS

The Scoli-RISK-1 study enrolled 272 ASD patients undergoing surgery from 15 centers. Inclusion criteria were Cobb angle of > 80°, corrective osteotomy for congenital/revision deformity, and/or 3-column osteotomy. At each follow-up visit, any neurologic or non-neurologic adverse event(AE) was documented & categorized.

RESULTS

77 patients had a minimum 5-year follow-up. 35 surgery-related AE's occurred during the 2 to 5-year period in 25(32.5%) patients. 23/35(65.7%) major, surgery-related complications occurred in 17 patients, 22/35(62.9%) requiring reoperations in 16 patients. Rod fracture and/or pseudarthrosis was the most common complication. The most common minor, surgery-related complication was asymptomatic rod fractures with no alignment changes. Four neurological complications were reported, one of which did not require reoperation. One death occurred at 6.1 years postoperative after multiple reoperations for mechanical complications. 14/17(82.4%) patients with major, surgery-related complication had a preceding AE during the initial 2-year postoperative period. 53 non-surgery-related AEs occurred in 21(27.3%) patients with musculoskeletal(37.7%) occurring most often. No differences were observed in ODI or SRS-22r in those with/without major surgery-related complications or those with/without reoperation.

CONCLUSION

During the study period, 25(32.5%) patients experienced 35 surgery-related complications, of which 23(65.7%) were major. Rod fracture with pseudarthrosis was the most common major, surgery-related complication. Neurologic complications were not found to be major drivers of reoperation. Surprisingly, PROs were similar in those with/without a major, surgery-related complication during the study period. This work has been presented as a podium presentation at the 55th Scoliosis Research Society annual meeting, Sep 9-13, 2020.

Use of Supplemental Rod Constructs in Adult Spinal Deformity Surgery: A Review

Adult spinal deformity comprises a heterogeneous group of disorders that primarily affects older patients and can have a significant negative affect on health-related quality of life. Operative treatment for adult spinal deformity typically entails posterior instrumented fusions that have demonstrated the potential to significantly improve health-related quality of life outcomes. However, until fusion is achieved, the instrumentation providing structural support is subject to repetitive cyclical loading that disproportionately fatigues high-stress areas and can result in instrumentation failure. Despite considerable advances in surgical fixation techniques and technology, pseudarthrosis with subsequent implant failure still poses a challenge for surgeons and continues to be 1 of the most common complications, leading to revision surgery. The addition of supplemental rods to primary constructs has gained widespread popularity to mitigate implant failure. Theoretically, more rods will add stiffness, stability, and decreased surface strain, which will provide longer instrumentation lifespan to allow for osseous fusion. There is significant heterogeneity in these constructs, and different types of supplemental rods (eg, satellite, accessory, delta rods, "kickstand rod," and "iliac accessory rod") can be used independently or in combination to further increase strength. However, the use of supplemental rods may increase the rate of proximal junctional kyphosis/failure and paradoxically diminish anterior column fusion rates. Hence, indications and optimal configurations are still a matter of debate. The aim of this narrative review is to provide an overview of the supplemental rod constructs described in the literature and focus on the current evidence supporting their indications and potential impact.

Adaptation, Validation, and Feasibility Evaluation of Mindful Standing Yoga Combined with Baduanjin for Older Patients with Primary Osteoporosis

OBJECTIVE

This study aimed to adapt, validate, and evaluate the feasibility of a mindful exercise program (Mindful Standing Yoga combined with Baduanjin) for older patients with primary osteoporosis.

METHODS

The study was conducted in 3 stages. Stage 1 involved a qualitative focus group discussion with 6 experts to gather perspectives on modifying the exercise program. Stage 2 used a Delphi approach with another 6 experts to validate the program. In Stage 3, a feasibility study was conducted with 20 eligible patients (out of 23 initially enrolled) at a traditional Chinese medicine hospital, using a single-group pre- and posttest design. The strenuousness of the adapted exercise was assessed through heart rate (HR) and rating of perceived exertion (RPE). Its effects were measured using the Global Pain Scale (GPS), the Five Facets Mindfulness Questionnaire-Short Form (FFMQ-SF), the Tampa Kinesiophobia-11 Scale, and the Timed Up and Go test. Patient satisfaction and feedback were also collected.

RESULTS

The modified program, consisting of 9 movements and taking 30 min to complete, was validated by experts as suitable, safe, and effective for practice. HR and RPE measurements confirmed it as a low-intensity exercise and not strenuous for the study population. The program significantly improved back pain and mindfulness in the feasibility study, with most participants expressing satisfaction with the protocol.

CONCLUSION

Experts and participants affirmed that the program was appropriate and satisfactory for older patients with primary osteoporosis, particularly those with back pain. Further high-quality randomized controlled trials are needed to validate its effectiveness.

Treatment of adult spine deformity: A retrospective comparison of bone morphogenic protein and bone marrow aspirate with bone allograft

BACKGROUND  : The use of bone morphogenic protein (BMP-2) in adult spine deformity (ASD) surgery remains controversial more than two decades following its approval for clinical application in spine surgery. This study was performed to assess outcomes in patients undergoing ASD surgery with BMP application compared with a combination of bone marrow aspirate, cancellous bone chips and i-Factor.

METHODS

This was a retrospective cohort study. ASD patients were stratified by use of intra-operative BMP (BMP +) or not (BMA + I) and surveyed for the development of complications and mechanical failure. Quality of life gained following the procedure was evaluated using quality-adjusted life years (QALYs). Cost was calculated using the PearlDiver database and CMS definitions. Multivariable analyses (ANCOVA) and logistic regression were used to adjust for confounding.

RESULTS

512 patients were included (60% BMP +). At baseline, BMP + patients were older (62.5 vs 60.8 years, p < 0.010). Radiographic and quality-of-life metrics did not differ at follow up timepoints (all p > 0.05). BMP use was associated with higher supplemental rod use (OR: 7.0, 1.9 - 26.2, p = 0.004), greater number of levels fused (OR: 1.1, 1.03 - 1.17, p = 0.003) and greater neurological complications (OR: 5.0, 1.3 - 18.7, p = 0.017). Controlling for rod use and levels fused, BMP use was not associated with a lower risk of mechanical complications (OR 0.3, 95% CI: 0.2 - 3.0, p = 0.353), rod breakage (OR: 3.3, 0.6 - 18.7, p = 0.182) or implant failure (OR: 0.3, 0.04 - 1.51). At 2 years, the BMP + cohort exhibited higher overall costs ($108,062 vs $95,144, p = 0.002), comparable QALYs (0.163 vs 0.171, p = 0.65) and higher cost per QALY (p = 0.001) at two years.

CONCLUSIONS

In this analysis, BMP-2 application was not associated with superior outcomes when compared to a less costly biologic alternative (bone marrow aspirate + cancellous bone chips + i-Factor) following ASD surgery. The use of BMP-2 in ASD surgery appears to have reduced cost-efficacy at two years postoperatively.

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

BACKGROUND AND OBJECTIVES

For patients with surgical adult spinal deformity (ASD), our understanding of alignment has evolved, especially in the last 20 years. Determination of optimal restoration of alignment and spinal shape has been increasingly studied, yet the assessment of how these alignment schematics have incrementally added benefit to outcomes remains to be evaluated.

METHODS

Patients with ASD with baseline and 2-year were included, classified by 4 alignment measures: Scoliosis Research Society (SRS)-Schwab, Age-Adjusted, Roussouly, and Global Alignment and Proportion (GAP). The incremental benefits of alignment schemas were assessed in chronological order as our understanding of optimal alignment progressed. Alignment was considered improved from baseline based on SRS-Schwab 0 or decrease in severity, Age-Adjusted ideal match, Roussouly current (based on sacral slope) matching theoretical (pelvic incidence-based), and decrease in proportion. Patients separated into 4 first improving in SRS-Schwab at 2-year, second Schwab improvement and matching Age-Adjusted, third two prior with Roussouly, and fourth improvement in all four. Comparison was accomplished with means comparison tests and χ 2 analyses.

RESULTS

Sevenhundredthirty-two. patients met inclusion. SRS-Schwab BL: pelvic incidence-lumbar lordosis mismatch (++:32.9%), sagittal vertical axis (++: 23%), pelvic tilt (++:24.6%). 640 (87.4%) met criteria for first, 517 (70.6%) second, 176 (24%) third, and 55 (7.5%) fourth. The addition of Roussouly (third) resulted in lower rates of mechanical complications and proximal junctional kyphosis (48.3%) and higher rates of meeting minimal clinically important difference (MCID) for physical component summary and SRS-Mental ( P < .05) compared with the second. Fourth compared with the third had higher rates of MCID for ODI (44.2% vs third: 28.3%, P = .011) and SRS-Appearance (70.6% vs 44.8%, P < .001). Mechanical complications and proximal junctional kyphosis were lower with the addition of Roussouly ( P = .024), while the addition of GAP had higher rates of meeting MCID for SRS-22 Appearance ( P = .002) and Oswestry Disability Index ( P = .085).

CONCLUSION

Our evaluation of the incremental benefit that alignment schemas have provided in ASD corrective surgery suggests that the addition of Roussouly provided the greatest reduction in mechanical complications, while the incorporation of GAP provided the most significant improvement in patient-reported outcomes.

Instrumentation Failure in Adult Spinal Deformity Patients

In recent years, advances in the surgical treatment of adult spinal deformity (ASD) have led to improved outcomes. Although these advances have helped drive the development of deformity surgery to meet the rising volume of patients seeking surgical treatment, many challenges have yet to be solved. Instrumentation failure remains one of the most common major complications following deformity surgery, associated with significant morbidity due to elevated re-operation rates among those experiencing mechanical complications. The two most frequently encountered subtypes of instrumentation failure are rod fracture (RF) and proximal junctional kyphosis/proximal junctional failure (PJK/PJF). While RF and PJK/PJF are both modes of instrumentation failure, they are two distinct entities with different clinical implications and treatment strategies. Considering that RF and PJK/PJF continue to represent a major challenge for patients with ASD and deformity surgeons alike, this review aims to discuss the incidence, risk factors, clinical impact, treatment strategies, preventive measures, and future research directions for each of these substantial complications.

Bone Quality as Measured by Hounsfield Units More Accurately Predicts Proximal Junctional Kyphosis than Vertebral Bone Quality Following Long-Segment Thoracolumbar Fusion

OBJECTIVE

To compare the prognostic power of Hounsfield units (HU) and Vertebral Bone Quality (VBQ) score for predicting proximal junctional kyphosis (PJK) following long-segment thoracolumbar fusion to the upper thoracic spine (T1-T6).

METHODS

Vertebral bone quality around the upper instrumented vertebrae (UIV) was measured using HU on preoperative CT and VBQ on preoperative MRI. Spinopelvic parameters were also categorized according to the Scoliosis Research Society-Schwab classification. Univariable analysis to identify predictors of the occurrence of PJK and survival analyses with Kaplan-Meier method and Cox regression were performed to identify predictors of time to PJK (defined as ≥10° change in Cobb angle of UIV+2 and UIV). Sensitivity analyses showed thresholds of HU < 164 and VBQ > 2.7 to be most predictive for PJK.

RESULTS

Seventy-six patients (mean age 66.0 ± 7.0 years; 27.6% male) were identified, of whom 15 suffered PJK. Significant predictors of PJK were high postoperative pelvic tilt (P = 0.038), high postoperative T1-pelvic angle (P = 0.041), and high postoperative PI-LL mismatch (P = 0.028). On survival analyses, bone quality, as assessed by the average HU of the UIV and UIV+1 was the only significant predictor of time to PJK (odds ratio [OR] 3.053; 95% CI 1.032-9.032; P = 0.044). VBQ measured using the UIV, UIV+1, UIV+2, and UIV-1 vertebrae approached, but did not reach significance (OR 2.913; 95% CI 0.797-10.646; P = 0.106).

CONCLUSIONS

In larger cohorts, VBQ may prove to be a significant predictor of PJK following long-segment thoracolumbar fusion. However, Hounsfield units on CT have greater predictive power, suggesting preoperative workup for long-segment thoracolumbar fusion benefits from computed tomography versus magnetic resonance imaging alone to identify those at increased risk of PJK.

Evaluation of lumbar paraspinal muscles degeneration and fatty infiltration in dynamic sagittal imbalance based on magnetic resonance imaging

PURPOSE

To explore degeneration and fatty infiltration (FI) of lumbar paraspinal muscles in patients with dynamic sagittal imbalance (DSI) and the relationship between lumbar paraspinal muscles degeneration, fatty infiltration and severity of the disease.

METHODS

We recruited 41 DSI patients and selected 22 lumbar spinal stenosis (LSS) patients without osphyalgia as controls. All patients received magnetic resonance imaging (MRI) scan and DSI patients also received pre-walk and post-walk X-rays. DSI patients were divided into 2 subgroups according to their symptom improvement after conservative treatment. We calculated rmCSA and FI of the lumbar paraspinal muscles. The rmCSA and FI between DSI and control and between DSI subgroups were compared by t test. The regression analysis was used to explore the risk factors influencing disease severity. Receiver operating characteristic (ROC) curves and area under curves (AUCs) were used to evaluate the severity of the disease.

RESULTS

In comparison of rmCSA and FI between DSI and control, there are significant differences of most muscles. In comparison of rmCSA between two subgroups, there are significant differences of most muscles, while in comparison of FI, only muscles in L4 segment have significant different. In logistic regression analysis, total rmCSA and total FI are risk factors influencing disease severity. ROC curves shows that total rmCSA and total FI both achieve an AUC greater than 0.7.

CONCLUSION

Compared with control, DSI patients have degeneration and fatty infiltration of the lumbar paraspinal muscles. The degeneration and fatty infiltration are risk factors influencing disease severity. The total rmCSA and total FI can be used as an indicator to determine whether a patient has severe DSI.

The Predictors of Incidental Durotomy in Patients Undergoing Pedicle Subtraction Osteotomy for the Correction of Adult Spinal Deformity

Background: Pedicle subtraction osteotomy (PSO) is a powerful tool for sagittal plane correction in patients with rigid adult spinal deformity (ASD); however, it is associated with high intraoperative blood loss and the increased risk of durotomy. The objective of the present study was to identify intraoperative techniques and baseline patient factors capable of predicting intraoperative durotomy. Methods: A tri-institutional database was retrospectively queried for all patients who underwent PSO for ASD. Data on baseline comorbidities, surgical history, surgeon characteristics and intraoperative maneuvers were gathered. PSO aggressiveness was defined as conventional (Schwab 3 PSO) or an extended PSO (Schwab type 4). The primary outcome of the study was the occurrence of durotomy intraoperatively. Univariable analyses were performed with Mann-Whitney U tests, Chi-squared analyses, and Fisher's exact tests. Statistical significance was defined by p < 0.05. Results: One hundred and sixteen patients were identified (mean age 61.9 ± 12.6 yr; 44.8% male), of whom 51 (44.0%) experienced intraoperative durotomy. There were no significant differences in baseline comorbidities between those who did and did not experience durotomy, with the exception that baseline weight and body mass index were higher in patients who did not suffer durotomy. Prior surgery (OR 2.73; 95% CI [1.13, 6.58]; p = 0.03) and, more specifically, prior decompression at the PSO level (OR 4.23; 95% CI [1.92, 9.34]; p < 0.001) was predictive of durotomy. A comparison of surgeon training showed no statistically significant difference in durotomy rate between fellowship and non-fellowship trained surgeons, or between orthopedic surgeons and neurosurgeons. The PSO level, PSO aggressiveness, the presence of stenosis at the PSO level, nor the surgical instrument used predicted the odds of durotomy occurrence. Those experiencing durotomy had similar hospitalization durations, rates of reoperation and rates of nonroutine discharge. Conclusions: In this large multisite series, a history of prior decompression at the PSO level was associated with a four-fold increase in intraoperative durotomy risk. Notably the use of extended (versus) standard PSO, surgical technique, nor baseline patient characteristics predicted durotomy. Durotomies occurred in 44% of patients and may prolong operative times. Additional prospective investigations are merited.

Modified posterior osteotomy for osteoporotic vertebral collapse with neurological dysfunction in thoracolumbar spine: a preliminary study

OBJECTIVE

The risk of osteoporotic vertebral collapse (OVC) associated with delayed neurological dysfunction (DND) is substantial, and performing surgery for this condition in elderly patients presents challenges. The focus of the current research is on simplifying surgical procedures while maintaining their effectiveness. This study was designed to contribute clinical data supporting the use of modified posterior osteotomy for treating thoracolumbar OVC with DND. The study compares perioperative clinical parameters, imaging data characteristics, and changes in efficacy outcome indicators to provide evidence for the advancement of this technique.

METHODS

A total of 12 patients diagnosed with osteoporotic vertebral collapse and neurological dysfunction were included in the study. All patients underwent modified posterior osteotomy. Data regarding perioperative and radiological parameters as well as complications such as surgery duration, blood loss, ASIA grade, VAS, ODI, regional kyphosis angle (RKA), anterior vertebral height ratio (AVHr), and spinal canal clearance ratio (SCCr), were collected retrospectively. These parameters were then analysed to evaluate the clinical efficacy and safety of the modified posterior osteotomy technique.

RESULTS

A total of 12 patients were included in the study, with a mean age of 65.5 ± 9.7 years. The average follow-up period was 29.4 ± 5.0 months. The mean operative blood loss was 483.3 ± 142.0 ml, and the average operative time was 3.7 ± 0.7 h. The visual analogue scale (VAS) score decreased from a preoperative value of 5.8 ± 0.7 to a final follow-up value of 1.3 ± 0.8 (P < 0.05), indicating a significant improvement in pain. The ODI decreased from 65.2 ± 6.0 before surgery to 20.5 ± 7.0, indicating a decrease in disability, and the postoperative neurological function showed a significant improvement. Correction of the RKA was observed, with the angle changing from 35.8 ± 10.8° before surgery to 20.0 ± 3.5° after surgery and to 22.5 ± 3.1° at the final follow-up. Similarly, correction of the AVHr was observed, with the height changing from 39.3 ± 18.0 to 63.0 ± 14.3 after surgery and to 53.9 ± 8.9 at the final follow-up. Correction of the SCCr was also observed, with the ratio changing from 54.9 ± 5.4 to 68.1 ± 5.3 after surgery and to 68.68 ± 6.76 at the final follow-up.

CONCLUSIONS

Posterior modified osteotomy is an effective treatment for thoracolumbar osteoporotic fractures with OVC combined with DND. It can significantly preserve vertebral height, increase vertebral canal volume, correct kyphotic angle, and improve postoperative neurological function. The simplified osteotomy also offers advantages in terms of operating time, blood loss, postoperative VAS score, and improvement in lumbar function.

Impact of Navigation on 30-Day Outcomes for Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective database study.

OBJECTIVE

Navigation has been increasingly used to treat degenerative disease, with positive radiographic and clinical outcomes and fewer adverse events and reoperations, despite increased operative time. However, short-term analysis on treating adult spinal deformity (ASD) surgery with navigation is limited, particularly using large nationally represented cohorts. This is the first large-scale database study to compare 30-day readmission, reoperation, morbidity, and value-per-operative time for navigated and conventional ASD surgery.

METHODS

Adults were identified in the National Surgical Quality Improvement Program (NSQIP) database. Multivariate regression was used to compare outcomes between navigated and conventional surgery and to control for predictors and baseline differences.

RESULTS

3190 ASD patients were included. Navigated and conventional patients were similar. Navigated cases had greater operative time (405 vs 320 min) and mean RVUs per case (81.3 vs 69.7), and had more supplementary pelvic fixations (26.1 vs 13.4%) and osteotomies (50.3 vs 27.7%) (P <.001).In univariate analysis, navigation had greater reoperation (9.9 vs 5.2%, P = .011), morbidity (57.8 vs 46.8%, P = .007), and transfusion (52.2 vs 41.8%, P = .010) rates. Readmission was similar (11.9 vs 8.4%). In multivariate analysis, navigation predicted reoperation (OR = 1.792, P = .048), but no longer predicted morbidity or transfusion. Most reoperations were infectious and hardware-related.

CONCLUSIONS

Despite controlling for patient-related and procedural factors, navigation independently predicted a 79% increased odds of reoperation but did not predict morbidity or transfusion. Readmission was similar between groups. This is explained, in part, by greater operative time and transfusion, which are risk factors for infection. Reoperation most frequently occurred for wound- and hardware-related reasons, suggesting navigation carries an increased risk of infectious-related events beyond increased operative time.

Proximal Junctional Kyphosis or Failure After Adult Spinal Deformity Surgery - Review of Risk Factors and Its Prevention

Proximal junction kyphosis (PJK) is a common imaging finding after long-level fusion, and proximal junctional failure (PJF) is an aggravated form of the progressive disease spectrum of PJK. This includes vertebral fracture of upper instrumented vertebra (UIV) or UIV+1, instability between UIV and UIV+1, neurological deterioration requiring surgery. Many studies have reported on PJK and PJF after long segment instrumentation for adult spinal deformity (ASD). In particular, for spine deformity surgeons, risk factors and prevention strategies of PJK and PJF are very important to minimize reoperation. Therefore, this review aims to help reduce the occurrence of PJK and PJF by updating the latest contents of PJK and PJF by 2023, focusing on the risk factors and prevention strategies of PJK and PJF. We conducted a search on multiple database for articles published until February 2023 using the search keywords "proximal junctional kyphosis," "proximal junctional failure," "proximal junctional disease," and "adult spinal deformity." Finally, 103 papers were included in this study. Numerous factors have been suggested as potential risks for the development of PJK and PJF, including a high body mass index, inadequate postoperative sagittal balance and overcorrection, advanced age, pelvic instrumentation, and osteoporosis. Recently, with the increasing elderly population, sarcopenia has been emphasized. The quality and quantity of muscle in the surgical site have been suggested as new risk factor. Therefore, spine surgeon should understand the pathophysiology of PJK and PJF, as well as individual risk factors, in order to develop appropriate prevention strategies for each patient.

Pelvic Fixation With a Quad-Rod Technique Using S2 Alar Iliac and Medialized Entry Iliac Screws for Long Fusion Constructs

PURPOSE

Patients with adult spinal deformity (ASD) may have risk factors for nonunion and subsequent instrumentation failure. This study reviews a novel surgical technique for a quad-rod construct to the pelvis using both S2 alar iliac (S2AI) screw fixation and medialized entry iliac screw fixation as described through three separate cases and a review of the literature.

METHODS

This technique facilitates alignment of the construct and rod insertion into the tulip heads. The medialized iliac screw technique also avoids the potential soft-tissue complications of the conventional iliac screw bolt given that it is deeper and has more soft-tissue coverage.

RESULTS

Three cases performed by the most senior author (V.A.) in which this novel technique was used are presented in this report along with clinical and radiographic images to educate the reader on appropriate execution of this technique. A review of the existing literature regarding pelvic fixation techniques for ASD was also done.

CONCLUSION

Quad-rod augmentation of long thoracolumbar spinal constructs with two independent SI anchoring points is potentially an effective technique to increase lumbar sacral construct rigidity, thereby promoting fusion rates and decreasing revision rates. The described technique provides spine surgeons with an additional tool in their armamentarium to treat patients with complex ASD.

Evaluation of the Thoracolumbar Injury Classification and Severity (TLICS) Score Over a Two-Year Period at a Level One Trauma Center

Introduction The use of the Thoracolumbar Injury Classification and Severity Score (TLICS) and other classification systems for guiding the management of traumatic spinal injuries remains controversial. TLICS is one of the few classifications that provides treatment recommendations.We sought to analyze intervention modality selection based on the TLICS scoring system. Methods A retrospective review of patients presenting with traumatic thoracolumbar fractures at a level 1 trauma center over a two-year period was performed. Primary endpoints for comparison analysis included visual analog scale (VAS) scores and Cobb angles during follow-up. Results There were 272 patients with thoracolumbar fractures, of whom 212 had TLICS of ≤3, six with TLICS of 4, and 54 with TLICS of ≥5. Of the 272 total patients, 59 were treated via surgery and 213 via non-surgical conservative methods. The VAS scores significantly decreased from presentation to last follow-up in both surgically treated and conservative groups (p<0.0001). This remained consistent in subgroup analyses of TLICS ≤ 3, TLICS = 4, and TLICS ≥ 5 (p<0.0001). Burst fractures treated conservatively had larger fracture Cobb angles versus those treated via surgery at the last follow-up, although this was not significantly associated (p=0.07). The only significant relationship with Cobb angles was in distraction fractures of the TLICS > 4 conservative group, who had significantly lower Cobb angles at the last follow-up than the TLICS > 4 surgical group (p<0.04). The "surgeon's choice" for TLICS = 4 was surgical intervention (4/6 patients, 66.7%). Conclusion Using the TLICS score, thoracolumbar injuries in a level 1 trauma center are more commonly TLICS ≤ 3. For patients with TLICS = 4, the surgeon's choice was most commonly surgical repair. VAS scores decreased over time from presentation between surgically and conservatively managed patients (as well as within-group analyses). The data concerning Cobb angles were more ambiguous, as larger Cobb angles in burst fractures treated conservatively did not show statistically significant differences with surgery.

Pelvic compensation accompanying spinal malalignment and back pain-related factors in a general population: the Wakayama spine study

Some older adults with spinal deformity maintain standing posture via pelvic compensation when their center of gravity moves forward. Therefore, evaluations of global alignment should include both pelvic tilt (PT) and seventh cervical vertebra-sagittal vertical axis (C7-SVA). Here, we evaluate standing postures of older adults using C7-SVA with PT and investigate factors related to postural abnormality. This cross-sectional study used an established population-based cohort in Japan wherein 1121 participants underwent sagittal whole-spine radiography in a standing position and bioelectrical impedance analysis for muscle mass measurements. Presence of low back pain (LBP), visual analog scale (VAS) of LBP, and LBP-related disability (Oswestry Disability Index [ODI]) were evaluated. Based on the PT and C7-SVA, the participants were divided into four groups: normal, compensated, non-compensated, and decompensated. We defined the latter three categories as "malalignment" and examined group characteristics and factors. There were significant differences in ODI%, VAS and prevalence of LBP, and sarcopenia among the four groups, although these were non-significant between non-compensated and decompensated groups on stratified analysis. Moreover, the decompensated group was significantly associated with sarcopenia. Individuals with pelvic compensation are at increased risk for LBP and related disorders even with the C7-SVA maintained within normal range.

Delayed stenosis associated with sublaminar band placement in the thoracic spine for proximal junctional kyphosis

Background

Proximal junctional thoracic kyphosis (PJK) is common following adult spinal deformity (ASD) surgery and may require revision operations. In this case series, we present delayed complications associated with the use of sublaminar banding (SLBs) for PJK prophylaxis.

Case Description

Three patients underwent long-segment thoracolumbar decompression and fusions for ASD. All had undergone SLB placement for PJK prophylaxis. All three subsequently developed neurologic complications secondary to cephalad spinal cord compression/stenosis requiring urgent revision surgery.

Conclusion

The placement of SLBs placed to prevent PJK may lead to sublaminar inflammation contributing to severe cephalad spinal canal stenosis and myelopathy following ASD surgery. Surgeons should be aware of this potential complication and may consider alternatives to SLB placement to avoid this complication.

Schroth Physiotherapeutic Scoliosis-Specific Exercise (PSSE) Trials-Systematic Review of Methods and Recommendations for Future Research

The Schroth method is a non-operative treatment for scoliosis and kyphosis, used standalone or as an adjunct to bracing. While supporting evidence for its effectiveness is emerging, methodologic standardization and rigor are equivocal. Thus, we aimed to systematically review methods of published Schroth physiotherapeutic scoliosis-specific exercise (PSSE) trials and provide guidance for future research. We searched six databases for randomized controlled trials (RCT) and non-randomized studies of interventions (NRSIs) investigating the effect of Schroth in children and adults with scoliosis or kyphosis. General characteristics, methodological approaches, treatment protocols, and outcomes reporting were analyzed. Risk of bias (RoB) was assessed using an adapted Cochrane RoB2 tool for RCTs and ROBINS-I for NRSI. Eligible studies (n = 7) were conducted in six countries and included patients with Scheuermann's kyphosis (n = 1) and adolescent idiopathic scoliosis (n = 6). Though all seven studies used the term Schroth to describe their interventions, the Schroth method was used in four of seven studies, of which only one used Schroth classification, three used Schroth therapists, and none prospectively registered the study protocol. Overall, methodological rigor was suboptimal, potentially invalidating evidence synthesis. Authors should follow minimum standards for reporting, including prospectively registering detailed protocols; using appropriate exercise labeling, Schroth classification and certified therapists; naming and describing exercises per classification; and providing therapy dosages, prescription methods, and adherence.

The Impact of Global Alignment and Proportion Score and Bracing on Proximal Junctional Kyphosis in Adult Spinal Deformity

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

The goal of this study is to examine the relationship between global alignment and proportion (GAP) score and postoperative orthoses with likelihood of developing proximal junctional kyphosis (PJK).

METHODS

Patients who underwent thoracic or lumbar fusions of ≥4 levels for adult spinal deformity (ASD) with 1-year post-operative alignment x-rays were included. Chart review was conducted to determine spinopelvic alignment parameters, PJK, and reoperation.

RESULTS

A total of 81 patients were included; baseline and 1-year postoperative alignment did not differ between patients with and without PJK. There was no PJK in 53.1%, 29.6% had PJK from 10-20°, and 17.3% had severe PJK over 20° (sPJK). At baseline, 80% of patients had severely disproportioned GAP, 13.75% moderate, 6.25% proportioned. GAP improved across the population, but improved GAP was not associated with sPJK. Greater correction of the upper instrumented vertebra to pelvic angle (UIV-PA) was associated with a larger PJK angle (PJKA) change (R = -0.28) as was the 1 year T1-upper instrumented vertebra (T1-UIV) angle (R = 0.30), both P < .05. GAP change was not correlated with PJKA change. Postoperative orthoses were used in 46% of patients and did not impact sPJK.

CONCLUSIONS

There was no correlation between PJK and GAP or change in GAP. Greater correction of UIV-PA and larger postop T1-UIV was associated with greater PJKA change; suggesting that the greater alignment correction led to greater likelihood of failure. Postoperative orthoses had no impact on PJK.

Proximal junctional failure in primary thoracolumbar fusion/fixation to the sacrum/pelvis for adult symptomatic lumbar scoliosis: long-term follow-up of a prospective multicenter cohort of 160 patients

OBJECTIVE

Proximal junctional failure (PJF) is a severe form of proximal junctional kyphosis. Previous reports on PJF have been limited by heterogeneous cohorts and relatively short follow-ups. The authors' objectives herein were to identify risk factors for PJF and to assess its long-term incidence and revision rates in a homogeneous cohort.

METHODS

The authors reviewed data from the Adult Symptomatic Lumbar Scoliosis 1 trial (ASLS-1), a National Institutes of Health-sponsored prospective multicenter study. Inclusion criteria were an age ≥ 40 years, ASLS (Cobb angle ≥ 30° and Oswestry Disability Index [ODI] ≥ 20 or Scoliosis Research Society revised 22-item questionnaire [SRS-22r] score ≤ 4.0 in pain, function, or self-image domains), and primary thoracolumbar fusion/fixation to the sacrum/pelvis of ≥ 7 levels. PJF was defined as a postoperative proximal junctional angle (PJA) change > 20°, fracture of the uppermost instrumented vertebra (UIV) or UIV+1 with > 20% vertebral height loss, spondylolisthesis of UIV/UIV+1 > 3 mm, or UIV screw dislodgment.

RESULTS

One hundred sixty patients (141 women) were included in this analysis and had a median age of 62 years and a mean follow-up of 4.3 years (range 0.1-6.1 years). Forty-six patients (28.8%) had PJF at a median of 0.92 years (IQR 0.14, 1.23 years) following surgery. Based on Kaplan-Meier analyses, PJF rates at 1, 2, 3, and 4 years were 14.4%, 21.9%, 25.9%, and 27.4%, respectively. On univariate analysis, PJF was associated with greater age (p = 0.0316), greater body mass index (BMI; p = 0.0319), worse baseline patient-reported outcome measures (PROMs; ODI, SRS-22r, and SF-12 Physical Component Summary [PCS]; all p < 0.04), the use of posterior column osteotomies (PCOs; p = 0.0039), and greater postoperative thoracic kyphosis (TK; p = 0.0031) and PJA (p < 0.001). The use of UIV hooks was protective against PJF (p = 0.0340). On regression analysis (without postoperative measures), PJF was associated with greater BMI (HR 1.077, 95% CI 1.007-1.153, p = 0.0317), lower preoperative PJA (HR 0.607, 95% CI 0.407-0.906, p = 0.0146), and greater preoperative TK (HR 1.362, 95% CI 1.082-1.715, p = 0.0085). Patients with PJF had worse PROMs at the last follow-up (ODI, SRS-22r subscore and self-image, and SF-12 PCS; p < 0.04). Sixteen PJF patients (34.8%) underwent revision, and PJF recurred in 3 (18.8%).

CONCLUSIONS

Among 160 primary ASLS patients with a median age of 62 years and predominant coronal deformity, the PJF rate was 28.8% at a mean 4.3-year follow-up, with a revision rate of 34.8%. On univariate analysis, PJF was associated with a greater age and BMI, worse baseline PROMs, the use of PCOs, and greater postoperative TK and PJA. The use of UIV hooks was protective against PJF. On multivariate analysis (without postoperative measures), a higher risk of PJF was associated with greater BMI and preoperative TK and lower preoperative PJA.

Early Postural Stability Changes in Patients Undergoing Correction of Spinal Deformity: A Prospective, Controlled Pilot Study

BACKGROUND CONTEXT

Adult spinal deformity (ASD) is a prevalent condition often requiring surgical intervention. Improved outcomes among ASD patients have been shown to correlate with postoperative spinopelvic parameters, yet little is currently known about the role of postural stability and balance assessment for ASD patients.

PURPOSE

Explore early changes in postural stability following ASD correction.

STUDY DESIGN

Prospective cohort study.

PATIENT SAMPLE

Sixteen adult patients who underwent four-level or greater posterolateral fusion to address global spinal malalignment and 14 healthy controls with no known spinal deformity nor surgery.

OUTCOME MEASURES

Postural stability parameters, spinopelvic parameters preoperatively and postoperatively.

METHODS

Force plate balance assessment was completed where participants and healthy controls were instructed to stand with their hands at their sides, standing still, with eyes open. Center of pressure (COP), center of gravity (COG), and cone of economy (COE) parameters were analyzed with paired and unpaired t tests with an alpha of 0.05.

RESULTS

Preoperatively, ASD patients demonstrated more COG (P=0.0244) and sagittal and coronal head (P<0.05) sway than healthy controls. Postoperatively, ASD patients exhibited less COP (P=0.0308), COG (P=0.0276) and head (P=0.0345) sway. Compared to healthy controls, ASD patients postoperatively exhibited similar postural stability, aside from COP and COG sway amplitudes (P<0.05), and coronal head sway (P=0.0309). Pelvic incidence-lumbar lordosis and sagittal vertical axis improved from 16.2° to 4.8° (P<0.01) and 82.2 to 22.5 mm (P<0.01), respectively.

CONCLUSION

We report a novel early improvement in postural stability, comparable to healthy controls, following ASD correction that may be related to improved spinopelvic alignment. Force plate evaluation may be a useful tool for ASD patients postoperatively. Future clinical trials assessing the impact of postural stability on clinical and radiographic outcomes are warranted.

Rod fractures in thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis: long-term follow-up of a prospective, multicenter cohort of 160 patients

OBJECTIVE

Previous reports of rod fracture (RF) in adult spinal deformity are limited by heterogeneous cohorts, low follow-up rates, and relatively short follow-up durations. Since the majority of RFs present > 2 years after surgery, true occurrence and revision rates remain unclear. The objectives of this study were to better understand the risk factors for RF and assess its occurrence and revision rates following primary thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis (ASLS) in a prospective series with long-term follow-up.

METHODS

Patient records were obtained from the Adult Symptomatic Lumbar Scoliosis-1 (ASLS-1) database, an NIH-sponsored multicenter, prospective study. Inclusion criteria were as follows: patients aged 40-80 years undergoing primary surgeries for ASLS (Cobb angle ≥ 30° and Oswestry Disability Index ≥ 20 or Scoliosis Research Society-22r ≤ 4.0 in pain, function, and/or self-image) with instrumented fusion of ≥ 7 levels that included the sacrum/pelvis. Patients with and without RF were compared to assess risk factors for RF and revision surgery.

RESULTS

Inclusion criteria were met by 160 patients (median age 62 years, IQR 55.7-67.9 years). At a median follow-up of 5.1 years (IQR 3.8-6.6 years), there were 92 RFs in 62 patients (38.8%). The median time to RF was 3.0 years (IQR 1.9-4.54 years), and 73% occurred > 2 years following surgery. Based on Kaplan-Meier analyses, estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Baseline radiographic, clinical, and demographic characteristics were similar between patients with and without RF. In Cox regression models, greater postoperative pelvic tilt (HR 1.895, 95% CI 1.196-3.002, p = 0.0065) and greater estimated blood loss (HR 1.02, 95% CI 1.005-1.036, p = 0.0088) were associated with increased risk of RF. Thirty-eight patients (61% of all RFs) underwent revision surgery. Bilateral RF was predictive of revision surgery (HR 3.52, 95% CI 1.8-6.9, p = 0.0002), while patients with unilateral nondisplaced RFs were less likely to require revision (HR 0.39, 95% CI 0.18-0.84, p = 0.016).

CONCLUSIONS

This study provides what is to the authors' knowledge the highest-quality data to date on RF rates following ASLS surgery. At a median follow-up of 5.1 years, 38.8% of patients had at least one RF. Estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Greater estimated blood loss and postoperative pelvic tilt were significant risk factors for RF. These findings emphasize the importance of long-term follow-up to realize the true prevalence and cumulative incidence of RF.

Unplanned Readmission Following Early Postoperative Complications After Fusion Surgery in Adult Spine Deformity: A Multicentric Study

STUDY DESIGN

Multicentric retrospective study, Level of evidence III.

OBJECTIVE

The objective of this multicentric study was to analyze the prevalence and risk factors of early postoperative complications in adult spinal deformity patients treated with fusion. Additionally, we studied the impact of complications on unplanned readmission and hospital length of stay.

METHODS

Eight spine centers from 6 countries in Latin America were involved in this study. Patients with adult spinal deformity treated with fusion surgery from 2017 to 2019 were included. Baseline and surgical characteristics such as age, sex, comorbidities, smoking, number of levels fused, number of surgical approaches were analyzed. Postoperative complications at 30 days were recorded according to Clavien-Dindo and Glassman classifications.

RESULTS

172 patients (120 females/52 males, mean age 59.4 ± 17.6) were included in our study. 78 patients suffered complications (45%) at 30 days, 43% of these complications were considered major. Unplanned readmission was observed in 35 patients (20,3%). Risk factors for complications were: Smoking, previous comorbidities, number of levels fused, two or more surgical approaches and excessive bleeding. Hospital length of stay in patients without and with complications was of 7.8 ± 13.7 and 17 ± 31.1 days, respectively (P 0.0001).

CONCLUSION

The prevalence of early postoperative complications in adult spinal deformity patients treated with fusion was of 45% in our study with 20% of unplanned readmissions at 30 days. Presence of complications significantly increased hospital length of stay.

Frailty measured by risk analysis index and adverse discharge outcomes after adult spine deformity surgery: analysis of 3104 patients from a prospective surgical registry (2011-2020)

BACKGROUND CONTEXT

Measurement of frailty with the Risk Analysis Index (RAI) has demonstrated improved outcome prediction compared to other frailty indices across the surgical literature. However, the generalizability and clinical utility of preoperative RAI scoring for prediction of postoperative morbidity after adult spinal deformity surgery is presently unknown. Thus, recent studies have called for an RAI analysis of spine deformity outcomes.

PURPOSE

The present study sought to evaluate the discriminatory accuracy of preoperative frailty, as measured by RAI, for predicting postoperative morbidity among adult spine deformity surgery patients using data queried from a large prospective surgical registry representing over 700 hospitals from 49 US states and 11 countries.

STUDY DESIGN/SETTING

Secondary analysis of a prospective surgical registry.

PATIENT SAMPLE

American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2011-2020).

OUTCOME MEASURES

The primary endpoint was "adverse discharge outcome" (ADO) defined as discharge to a non-home, non-rehabilitation nursing/chronic care facility.

METHODS

Adult spine deformity surgeries were queried from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2011-2020) using diagnosis and procedure codes. The relationship between increasing preoperative RAI frailty score and increasing rate of primary endpoint (ADO) was assessed with Cochran-Armitage linear trend tests. Discriminatory accuracy was tested by computation of concordance statistics (with 95% confidence interval [CI]) in receiver operating characteristic (ROC) curve analysis.

RESULTS

A total of 3,104 patients underwent spine deformity surgery and were stratified by RAI score: 0-10: 22%, 11-15: 11%, 16-20: 29%, 21-25: 26%, 26-30: 8.0%, 31-35: 2.4%, and 36+: 1.4%. The rate of ADO was 14% (N=439/3094). The rate of ADO increased significantly with increasing RAI score (p<.0001). RAI demonstrated robust discriminatory accuracy for prediction of ADO in ROC analysis (C-statistic: 0.71, 95% CI: 0.69-0.74, p<.001). In pairwise comparison of ROC curves (DeLong test), RAI demonstrates superior discriminatory accuracy compared to the 5-factor modified frailty index (mFI-5; p<.001).

CONCLUSION

Preoperative frailty, as measured by RAI, is a robust predictor of postoperative morbidity (measured by ADO) after adult spine deformity surgery. The frailty score may be translated directly to the bedside with a user-friendly risk calculator, deployed here: https://nsgyfrailtyoutcomeslab.shinyapps.io/spineDeformity.

Trans-intervertebral osteotomy classification of posterior spinal corrective osteotomy procedures via the intervertebral space

•This is a diagnostic study for a classification for posterior spinal osteotomy procedures via the intervertebral space.•Proposed ​a novel classification ​with ​excellent reliability ​and ​validity, differ from the SRS-Schwab osteotomy classification.•Give a novel definition of "trans-intervertebral osteotomy" (TIO) for posterior spinal osteotomy procedures.•Thoroughly discussed about the histories of posterior spinal osteotomy procedures via the intervertebral space.•Systematically introduced the TIO technique with fine original schematics.

GAP score potential in predicting post-operative spinal mechanical complications: a systematic review of the literature

PURPOSE

In 2017, the GAP score was proposed as a tool to reduce mechanical complications (MC) in adult spinal deformity (ASD) surgery: the reported MC rate for the GAP proportioned category was only 6%, which is clearly lower to the MC rate reported in the literature. The aim of this study is to analyse if the most recent literature confirms the promising results of the original article.

MATERIALS AND METHODS

Using the PRISMA flow chart, we reviewed the literature to analyse GAP score capacity in predicting MC occurrence. We included articles clearly reporting ASD surgery MC stratified by GAP categories and the score's overall capacity to predict MC using the area under the curve (AUC). The quality of the included studies was evaluated using GRADE and MINORS systems.

RESULTS

Eleven retrospective articles (1,517 patients in total) were included. The MC distribution per GAP category was as follows: GAP-P, 32.8%; GAP-MD, 42.3%; GAP-SD, 55.4%. No statistically significant difference was observed between the different categories using the Kruskal-Wallis test (p = 0.08) and the two-by-two Pearson-Chi square test (P Vs MD, p = 0.300; P Vs SD, p = 0.275; MD Vs SD, p = 0.137). The global AUC was 0.68 ± 0.2 (moderate accuracy). The included studies were of poor quality according to the GRADE system and had a high risk of bias based on the MINORS criteria.

CONCLUSION

The actual literature does not corroborate the excellent results reported by the original GAP score article. Further prospective studies, possibly stratified by type of MC and type of surgery, are necessary to validate this score.

Importance of physiological age in determining indications for adult spinal deformity surgery in patients over 75 years of age: a propensity score matching analysis

PURPOSE

Physiologically, people age at different rates, which leads to a discrepancy between physiological and chronological age. Physiological age should be a priority when considering the indications for adult spinal deformity (ASD) surgery. The primary objective of this study was to determine the characteristics of the postoperative course, surgical outcomes, and complication rates to extend the healthy life expectancy of older ASD patients (≥ 75 years). The secondary objective was to clarify the importance of physiological age in the surgical treatment of older ASD patients, considering frailty.

METHODS

A retrospective review of 109 consecutive patients aged ≥ 65 years with symptomatic ASD who underwent a corrective long fusion with lateral interbody fusion from the lower thoracic spine to the pelvis from 2015 to 2019 was conducted. Patients were classified into two groups according to age (group Y [65-74 years], group O [≥ 75 years]) and further divided into four groups according to the ASD-frailty index score (Y-F, Y-NF, O-F, and O-NF groups). To account for potential risk factors for perioperative course characteristics, complication rates, and surgical outcomes, patients from the database were subjected to propensity score matching based on sex, BMI, and preoperative sagittal spinal alignment (C7 sagittal vertical axis, pelvic incidence-lumbar lordosis, and pelvic tilt). Clinical outcomes were evaluated 2 years postoperatively, using three patient-reported outcome measures of health-related quality of life: the Oswestry Disability Index, Scoliosis Research Society questionnaire (SRS-22), and Short Form 36 (SF-36). Additionally, the postoperative time-to-first ambulation, as well as minor, major, and mechanical complications, were evaluated.

RESULTS

In the comparison between Y and O groups, patients in group O were at a higher risk of minor complications (delirium and urinary tract infection). In contrast, other surgical outcomes of group O were comparable to those of group Y, except for SRS-22 (satisfaction) and time to ambulation after surgery, with better outcomes in Group O. Patients in the O-NF group had better postoperative outcomes (time to ambulation after surgery, SRS-22 (function, self-image, satisfaction), SF-36 [PCS]) than those in the Y-F group.

CONCLUSIONS

Older age warrants monitoring of minor complications in the postoperative management of patients. However, the outcomes of ASD surgery depended more on frailty than on chronological age. Older ASD patients without frailty might tolerate corrective surgery and have satisfactory outcomes when minimally invasive techniques are used. Physiological age is more important than chronological age when determining the indications for surgery in older patients with ASD.

Adult Spinal Deformity: A Comprehensive Review of Current Advances and Future Directions

Owing to rapidly changing global demographics, adult spinal deformity (ASD) now accounts for a significant proportion of the Global Burden of Disease. Sagittal imbalance caused by age-related degenerative changes leads to back pain, neurological deficits, and deformity, which negatively affect the health-related quality of life (HRQoL) of patients. Along with the recognized regional, global, and sagittal spinopelvic parameters, poor paraspinal muscle quality has recently been acknowledged as a key determinant of the clinical outcomes of ASD. Although the Scoliosis Research Society-Schwab ASD classification system incorporates the radiological factors related to HRQoL, it cannot accurately predict the mechanical complications. With the rapid advances in surgical techniques, many surgical options for ASD have been developed, ranging from minimally invasive surgery to osteotomies. Therefore, structured patient-specific management is important in surgical decision-making, selecting the proper surgical technique, and to prevent serious complications in patients with ASD. Moreover, utilizing the latest technologies such as robotic-assisted surgery and machine learning, should help in minimizing the surgical risks and complications in the future.

Influence of Spinal Deformity Construct Design on Adjacent-Segment Biomechanics

BACKGROUND

Adjacent level degeneration is a precursor to construct failure in adult spinal deformity surgery, but whether construct design affects adjacent level degeneration risk remains unclear. Here we present a biomechanical profile of common deformity correction constructs and assess adjacent level biomechanics.

METHODS

Standard nondestructive flexibility tests (7.5 Nm) were performed on 21 cadaveric specimens: 14 pedicle subtraction osteotomies (PSOs) and 7 anterior column realignment (ACR) constructs. The ranges of motion (ROM) at the adjacent free level in flexion, extension, axial rotation, and lateral bending were measured and analyzed.

RESULTS

ACR constructs had a lower ROM change on flexion at the proximal adjacent free level than constructs with PSO (1.02 vs. 1.32, normalized to the intact specimen, P < 0.01). Lateral lumbar interbody fusion adjacent to PSO and 4 rods limits ROM at the free level more effectively than transforaminal interbody fusion and 2 rods in correction constructs with PSO. Use of 2 screws to anchor the ACR interbody further decreased ROM at the proximal adjacent free level on flexion, but adding 4 rods in this setting added no further limitation to adjacent segment motion.

CONCLUSIONS

ACR constructs have less ROM change at the adjacent level compared to PSO constructs. Among constructs with ACR, anchoring the ACR interbody with 2 screws reduces motion at the proximal adjacent free level. When PSOs are used, lateral lumbar interbody fusion adjacent to the PSO level has a greater reduction in adjacent-segment motion than transforaminal interbody fusion, suggesting that deformity construct configuration influences proximal adjacent-segment biomechanics.

Pedicle Subtraction Osteotomy in Adult Spinal Deformity: Comparing Fixed Versus Flexible Sagittal Imbalance

STUDY DESIGN/SETTING

Level III-retrospective radiologic and clinical comparative study.

OBJECTIVE

This study compares the results of pedicle subtraction osteotomy (PSO) for fixed versus flexible sagittal imbalance in adult spinal deformity.

SUMMARY OF BACKGROUND DATA

The result of PSO may be different according to the flexibility of the deformity.

METHODS

Sixty-one patients who underwent PSO were enrolled with a minimum 2-year follow-up. Twenty-one patients had fixed imbalance resulting from ankylosing spondylitis and iatrogenic flatback deformity, and 40 patients had flexible imbalance resulting from degenerative spinal deformity and posttraumatic kyphosis.

RESULTS

The mean age was 54.9±9.2 years in the fixed group and 65.9±10.5 years in the flexible group (P<0.01). PSO achieved about 35 degrees of correction of kyphotic angle in both groups, but the loss of correction (LOC) was higher in the flexible group. The correction of Lumbar Lordosis was similar in both groups, at 31.7±15.4 degrees in the fixed group and 32.3±20.8 degrees in the flexible group, although the LOC was also higher in the flexible group than in the fixed group, at 9.8±12.4 and 2.7±3.5 degrees, respectively (P<0.01). The sagittal vertical axis was much more restored in the fixed group than in the flexible group (P=0.002). Postoperative complications were identified in 4 patients in the fixed group, consisting of neurological deficit and screw loosening, and in 15 patients in the flexible group, consisting of proximal junctional kyphosis, screw pullout, rod fracture, and pseudarthrosis.

CONCLUSIONS

PSO for flexible sagittal imbalance resulted in a higher LOC of the osteotomy angle, Lumbar Lordosis, and sagittal vertical axis relative to the fixed deformity. Furthermore, more complications such as implant failure developed in the flexible group.

Multilevel Stabilization Screws Prevent Proximal Junctional Failure and Kyphosis in Adult Spinal Deformity Surgery: A Comparative Cohort Study

BACKGROUND

Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) occurred in up to 40% of patients with adult spinal deformity (ASD) who underwent open thoracolumbar fusion. Proximal stabilization techniques have been investigated to prevent PJK/PJF without conclusive results.

OBJECTIVE

To demonstrate reductions in PJK/PJF with multilevel stabilization screws (MLSSs).

METHODS

This observational longitudinal cohort study compares MLSSs with standard instrumentation. We reviewed the charts of consecutive patients with ASD undergoing open thoracolumbar fusion (>3 levels, extending cranially above T6 and caudally below L1) from 2009 to 2017 and were followed for >2 yr postoperatively. We defined PJF using the International Spine Study Group criteria and PJK as a Cobb angle increase >10°. We defined the upper instrumented vertebra as the most cephalad vertebral body with bilateral MLSSs. Confounders, MLSS-specific complications, and radiographic outcomes were collected. We evaluated comparability between groups using univariate analyses. We adjusted for covariates by using multivariable regressions modeling PJF and PJK separately with a P-value < .00625 considered significant after the Bonferroni correction. Sensitivity analysis accounted for those lost to follow-up.

RESULTS

Seventy-six patients (50 MLSS vs 26 controls) were included. MLSS patients were significantly older (64.5 ± 8.9 vs 54.8 ± 19.9 yr, P = .024) and had significantly lower PJF incidence (10.0% vs 30.8%, P = .023) and less kyphosis (1.3° ± 5.3° vs 5.2° ± 6.3°, P = .014). Multivariable analysis demonstrated a significant independent association between MLSSs and decreased odds of PJF (odds ratio: 0.11, 0.02-0.53, P = .006). Perioperative complications did not significantly differ between cohorts.

CONCLUSION

MLSSs are safe and efficacious in reducing PJF/PJK in patients with ASD undergoing open thoracolumbar fusion.

Orthopedic disease burden in adult patients with symptomatic lumbar scoliosis: results from a prospective multicenter study

OBJECTIVE

Although the health impact of adult symptomatic lumbar scoliosis (ASLS) is substantial, these patients often have other orthopedic problems that have not been previously quantified. The objective of this study was to assess disease burden of other orthopedic conditions in patients with ASLS based on a retrospective review of a prospective multicenter cohort.

METHODS

The ASLS-1 study is an NIH-sponsored prospective multicenter study designed to assess operative versus nonoperative treatment for ASLS. Patients were 40-80 years old with ASLS, defined as a lumbar coronal Cobb angle ≥ 30° and Oswestry Disability Index ≥ 20, or Scoliosis Research Society-22 questionnaire score ≤ 4.0 in pain, function, and/or self-image domains. Nonthoracolumbar orthopedic events, defined as fractures and other orthopedic conditions receiving surgical treatment, were assessed from enrollment to the 4-year follow-up.

RESULTS

Two hundred eighty-six patients (mean age 60.3 years, 90% women) were enrolled, with 173 operative and 113 nonoperative patients, and 81% with 4-year follow-up data. At a mean (± SD) follow-up of 3.8 ± 0.9 years, 104 nonthoracolumbar orthopedic events were reported, affecting 69 patients (24.1%). The most common events were arthroplasty (n = 38), fracture (n = 25), joint ligament/cartilage repair (n = 13), and cervical decompression/fusion (n = 7). Based on the final adjusted model, patients with a nonthoracolumbar orthopedic event were older (HR 1.44 per decade, 95% CI 1.07-1.94), more likely to have a history of tobacco use (HR 1.63, 95% CI 1.00-2.66), and had worse baseline leg pain scores (HR 1.10, 95% CI 1.01-1.19).

CONCLUSIONS

Patients with ASLS have high orthopedic disease burden, with almost 25% having a fracture or nonthoracolumbar orthopedic condition requiring surgical treatment during the mean 3.8 years following enrollment. Comparisons with previous studies suggest that the rate of total knee arthroplasty was considerably greater and the rates of total hip arthroplasty were at least as high in the ASLS-1 cohort compared with the similarly aged general US population. These conditions may further impact health-related quality of life and outcomes assessments of both nonoperative and operative treatment approaches in patients with ASLS.

Posterior instrumented fusion on lumbar stenosis syndrome can bring benefit to proximal degenerative kyphosis: A CONSORT-compliant article

ABSTRACT

The effect on degenerative thoracolumbar kyphosis (DTLK) after short-segment instrument for lumbar spinal stenosis syndrome (LSS) remains controversial. Based on the biomechanics and compensatory of the global spino-pelvic alignment, it was assumed that the interference on the lumbar spine, instead of the thoracolumbar segment, could still make a difference on the proximal spine.To explore whether DTLK could improve with only surgery for LSS and identify influencing factors on postoperative TLK.The study was performed from January 2016 to December 2018. Sixty-nine participants (25 male) diagnosed LSS with DTLK were enrolled and surgery was only for LSS. Radiological parameters included TLK, lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, and osteoporosis. Clinical outcomes were visual analogue scale and Oswestry disability index. According to lower instrumented vertebrae (LIV) on L5 or S1, inter-group comparisons were performed between LIV on L5 (L5 group) and S1 (S1 group).Demographics were well-matched between L5 and S1 group with a mean follow-up of 24.3 ± 12.1 (m). TLK improved with a mean of 16.2 ± 7.6 (°) (P < .001). There was no significance on radiological and clinical parameters between L5 and S1 groups except for a larger pelvic tilt in S1 group (P = .046). Visual analogue scale (P = .787) and Oswestry disability index (P = .530) were both indifferent between normal TLK and DTLK at last (P > .05). Postoperative TLK was affected by osteoporosis and sacral slope, the latter was dominated by pelvic incidence and pelvic rotation. Osteoporosis was the risk factor for TLK correction (P = .001, odd risk = 9.58).DTLK decreased if instrument only performed for LSS, where TLK and clinical outcomes are comparably affected whether L5 or S1 is selected as LIV. This study supplements the compensatory mechanism of spino-pelvic alignment, especially for cases with severe osteoporosis.

Emerging Technologies in the Treatment of Adult Spinal Deformity

Outcomes for adult spinal deformity continue to improve as new technologies become integrated into clinical practice. Machine learning, robot-guided spinal surgery, and patient-specific rods are tools that are being used to improve preoperative planning and patient satisfaction. Machine learning can be used to predict complications, readmissions, and generate postoperative radiographs which can be shown to patients to guide discussions about surgery. Robot-guided spinal surgery is a rapidly growing field showing signs of greater accuracy in screw placement during surgery. Patient-specific rods offer improved outcomes through higher correction rates and decreased rates of rod breakage while decreasing operative time. The objective of this review is to evaluate trends in the literature about machine learning, robot-guided spinal surgery, and patient-specific rods in the treatment of adult spinal deformity.

A Novel Weave Tether Technique for Proximal Junctional Kyphosis Prevention in 71 Adult Spinal Deformity Patients: A Preliminary Case Series Assessing Early Complications and Efficacy

BACKGROUND

Proximal junctional kyphosis (PJK) rates may be as high as 69.4% after adult spinal deformity (ASD) surgery. PJK is one of the greatest unsolved challenges in long-segment fusions for ASD and remains a common indication for costly and impactful revision surgery. Junctional tethers may help to reduce the occurrence of PJK by attenuating adjacent-segment stress.

OBJECTIVE

To report our experience and assess early safety associated with a novel "weave-tether technique" (WTT) for PJK prophylaxis in a large series of patients.

METHODS

This single-center retrospective study evaluated consecutive patients who underwent ASD surgery including WTT between 2017 and 2018. Patient demographics, operative details, standard radiographic measurements, and complications were analyzed.

RESULTS

A total of 71 patients (mean age 66 ± 12 yr, 65% women) were identified. WTT included application to the upper-most instrumented vertebrae (UIV) + 1 and UIV + 2 in 38(53.5%) and 33(46.5%) patients, respectively. No complications directly attributed to WTT usage were identified. For patients with radiographic follow-up (96%; mean duration 14 ± 12 mo), PJK occurred in 15% (mean 1.8 ± 1.0 mo postoperatively). Proximal junctional angle increased an average 4° (10° to 14°, P = .004). Rates of symptomatic PJK and revision for PJK were 8.8% and 2.9%, respectively.

CONCLUSION

Preliminary results support the safety of the WTT for PJK prophylaxis. Approximately 15% of patients developed radiographic PJK, no complications were directly attributed to WTT usage, and the revision rate for PJK was low. These early results warrant future research to assess longer-term efficacy of the WTT for PJK prophylaxis in ASD surgery.

Sustainable Technologies for Older Adults

The exponential evolution of technology and the growth of the elderly population are two phenomena that will inevitably interact with increasing frequency in the future. This paper analyses scientific literature as a means of furthering progress in sustainable technology for senior living. We carried out a bibliometric analysis of papers published in this area and compiled by the Web of Science (WOS) and Scopus, examining the main participants and advances in the field from 2000 to the first quarter of 2021. The study describes some interesting research projects addressing three different aspects of older adults’ daily lives—health, daily activities and wellbeing—and policies to promote healthy aging and improve the sustainability of the healthcare system. It also looks at lines of research into transversal characteristics of technology. Our analysis showed that publications mentioning sustainability technologies for older adults have been growing progressively since the 2000s, but that the big increase in the number of research works in this area took place during the period 2016–2021. These more recent works show a tendency to study those factors that improve healthy aging, ensure the social inclusion of the elderly through technology and prolong the time in which they can live independent lives thanks to smart environments. Current research gaps in the literature are also discussed.

Operative versus nonoperative treatment for adult symptomatic lumbar scoliosis at 5-year follow-up: durability of outcomes and impact of treatment-related serious adverse events

OBJECTIVE

Although short-term adult symptomatic lumbar scoliosis (ASLS) studies favor operative over nonoperative treatment, longer outcomes are critical for assessment of treatment durability, especially for operative treatment, because the majority of implant failures and nonunions present between 2 and 5 years after surgery. The objectives of this study were to assess the durability of treatment outcomes for operative versus nonoperative treatment of ASLS, to report the rates and types of associated serious adverse events (SAEs), and to determine the potential impact of treatment-related SAEs on outcomes.

METHODS

The ASLS-1 (Adult Symptomatic Lumbar Scoliosis-1) trial is an NIH-sponsored multicenter prospective study to assess operative versus nonoperative ASLS treatment. Patients were 40-80 years of age and had ASLS (Cobb angle ≥ 30° and Oswestry Disability Index [ODI] ≥ 20 or Scoliosis Research Society [SRS]-22 subscore ≤ 4.0 in the Pain, Function, and/or Self-Image domains). Patients receiving operative and nonoperative treatment were compared using as-treated analysis, and the impact of related SAEs was assessed. Primary outcome measures were ODI and SRS-22.

RESULTS

The 286 patients with ASLS (107 with nonoperative treatment, 179 with operative treatment) had 2-year and 5-year follow-up rates of 90% (n = 256) and 74% (n = 211), respectively. At 5 years, compared with patients treated nonoperatively, those who underwent surgery had greater improvement in ODI (mean difference -15.2 [95% CI -18.7 to -11.7]) and SRS-22 subscore (mean difference 0.63 [95% CI 0.48-0.78]) (p < 0.001), with treatment effects (TEs) exceeding the minimum detectable measurement difference (MDMD) for ODI (7) and SRS-22 subscore (0.4). TEs at 5 years remained as favorable as 2-year TEs (ODI -13.9, SRS-22 0.52). For patients in the operative group, the incidence rates of treatment-related SAEs during the first 2 years and 2-5 years after surgery were 22.38 and 8.17 per 100 person-years, respectively. At 5 years, patients in the operative group who had 1 treatment-related SAE still had significantly greater improvement, with TEs (ODI -12.2, SRS-22 0.53; p < 0.001) exceeding the MDMD. Twelve patients who received surgery and who had 2 or more treatment-related SAEs had greater improvement than nonsurgically treated patients based on ODI (TE -8.34, p = 0.017) and SRS-22 (TE 0.32, p = 0.029), but the SRS-22 TE did not exceed the MDMD.

CONCLUSIONS

The significantly greater improvement of operative versus nonoperative treatment for ASLS at 2 years was durably maintained at the 5-year follow-up. Patients in the operative cohort with a treatment-related SAE still had greater improvement than patients in the nonoperative cohort. These findings have important implications for patient counseling and future cost-effectiveness assessments.

Kitchen elbow sign predicts surgical outcomes in adults with spinal deformity: a retrospective cohort study

Kitchen elbow sign (KE-Sign) is a skin abnormality on the extensor side of the elbow and forearm that is often observed in patients with adult spinal deformity (ASD). The significance of KE-Sign in surgical cases was investigated. Overall, 114 patients with ASD treated with long spinal fusion were reviewed and divided into KE-Sign positive and negative groups. The preoperative and 1-year follow-up evaluations included radiographic parameters [C7 sagittal vertical axis (SVA), pelvic incidence (PI) and lumbar lordosis (LL)], the Oswestry Disability Index (ODI), visual analogue scales (VASs) for low back pain, leg pain, and satisfaction, and Short Form 36 questionnaire (SF-36). Multi-regression analysis was performed to identify patient satisfaction predictors and improvement in the ODI as dependent variables and preoperative background factors as independent variables. Preoperative characteristics showed no significant difference between both groups. Improvement in the ODI and VAS for satisfaction were significantly superior in the KE-Sign positive group. In multiple regression analysis, KE-Sign and preoperative ODI were significantly associated with improvement in the ODI; age, KE-Sign, preoperative low back pain VAS, and leg pain VAS were significantly associated with satisfaction. KE-Sign can be a predictor of better surgical outcomes in ASD patients.

Deep Learning Automates Measurement of Spinopelvic Parameters on Lateral Lumbar Radiographs

STUDY DESIGN

Cross-sectional database study.

OBJECTIVE

The objective of this study was to develop an algorithm for the automated measurement of spinopelvic parameters on lateral lumbar radiographs with comparable accuracy to surgeons.

SUMMARY OF BACKGROUND DATA

Sagittal alignment measurements are important for the evaluation of spinal disorders. Manual measurement methods are time-consuming and subject to rater-dependent error. Thus, a need exists to develop automated methods for obtaining sagittal measurements. Previous studies of automated measurement have been limited in accuracy, inapplicable to common plain films, or unable to measure pelvic parameters.

METHODS

Images from 816 patients receiving lateral lumbar radiographs were collected sequentially and used to develop a convolutional neural network (CNN) segmentation algorithm. A total of 653 (80%) of these radiographs were used to train and validate the CNN. This CNN was combined with a computer vision algorithm to create a pipeline for the fully automated measurement of spinopelvic parameters from lateral lumbar radiographs. The remaining 163 (20%) of radiographs were used to test this pipeline. Forty radiographs were selected from the test set and manually measured by three surgeons for comparison.

RESULTS

The CNN achieved an area under the receiver-operating curve of 0.956. Algorithm measurements of L1-S1 cobb angle, pelvic incidence, pelvic tilt, and sacral slope were not significantly different from surgeon measurement. In comparison to criterion standard measurement, the algorithm performed with a similar mean absolute difference to spine surgeons for L1-S1 Cobb angle (4.30° ± 4.14° vs. 4.99° ± 5.34°), pelvic tilt (2.14° ± 6.29° vs. 1.58° ± 5.97°), pelvic incidence (4.56° ± 5.40° vs. 3.74° ± 2.89°), and sacral slope (4.76° ± 6.93° vs. 4.75° ± 5.71°).

CONCLUSION

This algorithm measures spinopelvic parameters on lateral lumbar radiographs with comparable accuracy to surgeons. The algorithm could be used to streamline clinical workflow or perform large scale studies of spinopelvic parameters.Level of Evidence: 3.

Strategies for prevention of rod fracture in adult spinal deformity: cobalt chrome rod, accessory rod technique, and lateral lumbar interbody fusion

OBJECTIVE

Restoring the proper sagittal alignment in adult spinal deformity (ASD) can improve radiological and clinical outcomes, but pseudarthrosis including rod fracture (RF) is a common problematic complication. The purpose of this study was to analyze the methods for reducing the incidence of RF in deformity correction of ASD.

METHODS

The authors retrospectively selected 178 consecutive patients (mean age 70.8 years) with lumbar degenerative kyphosis (LDK) who underwent deformity correction with a minimum 2-year follow-up. Patients were classified into the non-RF group (n = 131) and the RF group (n = 47). For predicting the crucial factors of RF, patient factors, radiographic parameters, and surgical factors were analyzed.

RESULTS

The overall incidence of RF was 26% (47/178 cases), occurring in 42% (42/100 cases) of pedicle subtraction osteotomy (PSO), 7% (5/67 cases) of lateral lumbar interbody fusion (LLIF) with posterior column osteotomy, 18% (23/129 cases) of cobalt chrome rods, 49% (24/49 cases) of titanium alloy rods, 6% (2/36 cases) placed with the accessory rod technique, and 32% (45/142 cases) placed with the 2-rod technique. There were no significant differences in the incidence of RF regarding patient factors between two groups. While both groups showed severe sagittal imbalance before operation, lumbar lordosis (LL) was more kyphotic and pelvic incidence (PI) minus LL (PI-LL) mismatch was greater in the RF group (p < 0.05). Postoperatively, while LL and PI-LL did not show significant differences between the two groups, LL and sagittal vertical axis correction were greater in the RF group (p < 0.05). Nonetheless, at the last follow-up, the two groups did not show significant differences in radiographic parameters except thoracolumbar junctional angles. As for surgical factors, use of the cobalt chrome rod and the accessory rod technique was significantly greater in the non-RF group (p < 0.05). As for the correction method, PSO was associated with more RFs than the other correction methods, including LLIF (p < 0.05). By logistic regression analysis, PSO, preoperative PI-LL mismatch, and the accessory rod technique were crucial factors for RF.

CONCLUSIONS

Greater preoperative sagittal spinopelvic malalignment including preoperative PI-LL mismatch was the crucial risk factor for RF in LDK patients 65 years or older. For restoring and maintaining sagittal alignment, use of the cobalt chrome rod, accessory rod technique, or LLIF was shown to be effective for reducing RF in ASD surgery.

Cost-Effectiveness of Adult Spinal Deformity Surgery

STUDY DESIGN

Review article.

OBJECTIVE

A review of the literature evaluating the cost-effectiveness of undergoing adult spinal deformity surgery and potential avenues for reducing costs.

METHODS

A review of the current literature and synthesis of data to provide an update on the cost effectiveness of undergoing adult spinal deformity surgery.

RESULTS

Compared with nonoperative management, operative management for adult spinal deformity is associated with improved patient-reported outcomes and quality of life; however, it is associated with significant financial and resource use.

CONCLUSION

Operative management for adult spinal deformity has been shown to be effective but is associated with significant cost and resource utilization. The optimal operative treatment is highly dependent on the patients' symptomatology and is surgeon dependent. Maximizing preoperative surgical health and minimizing postoperative complications are key measures in reducing the cost and resource utilization of adult spinal deformity surgery. Future studies are needed to evaluate how to optimize the cost-effectiveness.

Postoperative Complication Burden, Revision Risk, and Health Care Use in Obese Patients Undergoing Primary Adult Thoracolumbar Deformity Surgery

STUDY DESIGN

This is a retrospective cohort study using a nationally representative administrative database.

OBJECTIVE

To identify the impact of obesity on postoperative outcomes in patients undergoing thoracolumbar adult spinal deformity (ASD) surgery.

BACKGROUND

The obesity rate in the United States remains staggering, with approximately one-third of all Americans being overweight or obese. However, the impact of elevated body mass index on spine surgery outcomes remains unclear.

METHODS

We queried the MarketScan database to identify patients who were diagnosed with a spinal deformity and underwent ASD surgery from 2007 to 2016. Patients were then stratified by whether or not they were diagnosed as obese at index surgical admission. Propensity score matching (PSM) was then utilized to mitigate intergroup differences between obese and nonobese patients. Patients <18 years and those with any prior history of trauma or tumor were excluded from this study. Baseline demographics and comorbidities, postoperative complication rates, and short- and long-term reoperation rates were determined.

RESULTS

A total of 7423 patients met the inclusion criteria of this study, of whom 597 (8.0%) were obese. Initially, patients with obesity had a higher 90-day postoperative complication rate than nonobese patients (46.1% vs 40.8%, P < .05); however, this difference did not remain after PSM. Revision surgery rates after 2 years were similar across the 2 groups following primary surgery (obese, 21.4%, vs nonobese, 22.0%; P = .7588). Health care use occurred at a higher rate among obese patients through 2 years of long-term follow-up (obese, $152 930, vs nonobese, $140 550; P < .05).

CONCLUSION

Patients diagnosed with obesity who underwent ASD surgery did not demonstrate increased rates of complications, reoperations, or readmissions. However, overall health care use through 2 years of follow-up after index surgery was higher in the obesity cohort.

Surgery for spinal deformity: non-elective admission status is associated with higher cost of care and longer length of stay

INTRODUCTION

Surgery is commonly indicated for adult spinal deformity. Annual rates and costs of spinal deformity surgery have both increased over the past two decades. However, the impact of non-elective status on total cost of hospitalization and patient outcomes has not been quantified.

OBJECTIVE

To evaluate the impact of admission status on patient outcomes and healthcare costs in spinal deformity surgery.

METHODS

All patients who underwent spinal deformity surgery at a single institution between 2008 and 2016 were grouped by admission status: elective, emergency (ED), or transferred. Demographics were compared by univariate analysis. Cost of care and length of stay (LOS) were compared between admission statuses using multivariable linear regression with elective admissions as reference. Multivariate logistic regression was utilized to assess in-hospital complications, discharge destination, and readmission rates.

RESULTS

There were 427 spinal deformity surgeries included in this study. Compared to elective patients, ED patients had higher Elixhauser Comorbidity Index scores (p < 0.0001), longer LOS (+ 10.9 days, 97.5% CI 6.1-15.6 days, p < 0.0001), and higher costs (+ $20,076, 97.5% CI $9,073-$31,080, p = 0.0008). Transferred patients had significantly higher Elixhauser scores (p = 0.0002), longer LOS (+ 8.8 days, 97.5% CI 3.0-14.7 days, p < 0.0001), and higher rates of non-home discharge (OR = 15.8, 97.5% CI 2.3-110.0, p = 0.001).

CONCLUSION

Patients admitted from the ED undergoing spinal deformity surgery had significantly higher cost of care and longer LOS compared to elective patients. Transferred patients had significantly longer LOS and a higher rate of non-home discharge compared to elective patients.

Representative dynamic ranges of spinal alignment during gait in patients with mild and severe adult spinal deformities

BACKGROUND CONTEXT

Surgical correction strategies for adult spinal deformity (ASD) relies heavily on radiographic alignment goals, however, there is often debate regarding degree of correction and how static alignment translates to physical ability in daily life. Kinematic analysis has the potential to improve the concept of ideal spinal alignment by providing clinically meaningful estimates of dynamic changes in spinal alignment during activities of daily life.

PURPOSE

Estimate representative dynamic ranges of spinal alignment during gait among ASD patients using 3D motion tracking; compare dynamic alignment between mild and severe deformity patients and to healthy adults.

STUDY DESIGN/SETTING

Retrospective review at a single institution.

PATIENT SAMPLE

Fifty-two ASD patients and 46 healthy adults.

OUTCOME MEASURES

Radiographic alignment, kinematic spine motion, spatiotemporal gait measures, patient reported outcomes (VAS pain, ODI, SRS-22r).

METHODS

Spinal alignment was assessed radiographically and during standing and overground walking tests. Dynamic alignment was initialized by linking radiographic alignment to kinematic alignment during standing and at initial heel contact during gait. Dynamic changes in maximums and minimums during gait were made relative to initial heel contact for each gait cycle. Total range-of-motion (RoM) was measured for both ASD and healthy subjects. Dynamic alignment measures included coronal and sagittal vertical axes (CVA, SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), and pelvic tilt (PT). ASD patient's deformities were classified as either Mild or Severe based on the SRS-Schwab ASD classification.

RESULTS

Severe ASD patients had significantly larger dynamic maximum and minimums for SVA, TPA, LL, and PT (all p<.05) compared with Mild ASD patients. ASD patients exhibited little difference in dynamic alignment compared with healthy subjects. Only PT had a significant difference in dynamic RoM compared with healthy (p<.001).

CONCLUSIONS

Mild and Severe ASD patients exhibited similar global dynamic alignment measures during gait and had comparable RoM to healthy subjects except with greater PT and reduced spatiotemporal performance which may be key compensatory mechanisms for dynamic stabilization.