Evolution and Advancement of Adult Spinal Deformity Research and Clinical Care: An Overview of the Scoli-RISK-1 Study

Effect of Spinal Cord Compression and Deformation on Postoperative Neurological Deficits During Spinal Deformity Correction Surgery

Study DesignRetrospective comparative analysis.ObjectiveTo evaluate the impact of the spinal cord deformation rate (SCDR) on postoperative neurological deficits (PNDs) in spinal deformity surgery and to determine the optimal SCDR threshold for risk stratification.MethodsPatients undergoing corrective surgery between October 2010 and March 2022 were included. Spinal cord morphology at the apex was assessed using axial T2-weighted magnetic resonance imaging, categorizing spinal cords into type-A and type-B. Differences between the two groups were analyzed and the odds ratio (OR) for PNDs in patients with type-B was calculated. For patients classified as type-B, univariate analysis was conducted to identify variables, including SCDR, that may influence PNDs risk. Statistically significant variables were further analyzed using multivariate analysis. The receiver operating characteristic (ROC) curve and area under the curve (AUC) analyses were performed to evaluate the discriminative ability of risk factors and determine the optimal cut-off value.ResultsAmong 200 patients included, PNDs occurred in 17 cases (8.5%), predominantly in type-B (15/82 in type-B vs 2/118 in type-A, P < 0.001). Multivariate analysis revealed SCDR as an independent predictor of PNDs (OR = 1.076, P = 0.001). ROC analysis determined an optimal SCDR cutoff of 42.15% (AUC: 0.867), with 82.4% sensitivity, 88.5% specificity, and 98.2% negative predictive value (NPV). SCDR demonstrated superior predictive performance compared to the major Cobb angle (AUC: 0.776) and T-DAR (AUC: 0.769).ConclusionsFor patients undergoing corrective surgery, an SCDR of ≥42.15% serves as a strong predictor of PNDs. Its high NPV effectively excludes low-risk patients, offering improved risk stratification.

Impact of Enhanced Recovery After Surgery Protocols on Outcomes Up to Two Years After Adult Structural Spine Disorder Surgery

STUDY DESIGN

Retrospective cohort study of prospectively enrolled database.

OBJECTIVE

We analyze the recovery pattern of patients with adult structural spine disorder (ASD) who underwent corrective surgery with enhanced recovery after surgery (ERAS+) protocol, including physical and psychological prehabilitation components, compared with a non-ERAS protocol (ERAS-) up to 2 years (2Y) after surgery.

BACKGROUND

Spine surgery for ASD is often highly invasive, which can contribute to prolonged recovery. The trajectory of recovery may be accelerated by the application of enhanced recovery principles.

MATERIALS AND METHODS

Inclusion criteria were operative patients with ASD older than 18 years with complete baseline, 90 days perioperative, and 2Y postoperative data. We assessed differences in baseline demographics, surgical details, baseline health-related quality of life (HRQL), and surgical outcomes between ERAS+ and ERAS- patients. Outcomes included adverse events, reoperations, and radiographic parameters such as sacral slope, pelvic tilt, pelvic incidence-lumbar lordosis mismatch, sagittal vertical axis, lumbar lordosis, T2 to T12 kyphosis, and maximum Cobb angle. In addition, HRQL measures included the physical component summary, Oswestry Disability Index, Neck Disability Index, EuroQol 5 dimensions, Scoliosis Research Society Questionnaire 22r total and domain scores, Numeric Pain Rating Scale-back, and Numeric Pain Rating Scale-leg. We used multivariable logistic regression and analysis of covariance to adjust for confounding.

RESULTS

A total of 471 patients with ASD met the inclusion criteria, with 59 designated ERAS+. Those individuals with ERAS+ were older (64.1 ± 13.0 vs. 58.0 ± 16.0; P = 0.005), had a higher Charlson Comorbidity Index, (2.4 ± 1.8 vs. 1.4 ± 1.6; P < 0.001), and exhibited a higher modified ASD frailty index (8.2 ± 5.4 vs. 6.3 ± 4.9; P = 0.019). The adjusted analysis demonstrated the ERAS+ cohort demonstrated a lower likelihood of overall reoperations (Odds ratio (OR): 0.3; 95% CI: 0.13-0.89), and a lower likelihood of overall adverse events (OR: 0.4; 95% CI: 0.19-0.93). ERAS+ was more likely to achieve the minimal clinically important difference in the Scoliosis Research Society Questionnaire 22r total scores at 6 months (6M; OR: 3.1; 95% CI: 1.2-8.4), self-image domain at 6M (OR: 9.0; 95% CI: 1.6-50.0), in the pain domain at 6M (OR: 3.5; 95% CI: 1.01-11.9) and 1 year postoperatively (OR: 2.6; 95% CI: 1.03-6.7), and in the SF-36's physical component summary (PCS) scores at 1 year (OR: 2.1; 95% CI: 1.05-4.2). No other statistically significant differences in HRQL were observed at the remaining time points (P > 0.05).

CONCLUSION

Our work is the first to evaluate HRQL metrics and complications over 2Y following ASD correction with ERAS. Despite presenting with more severe baseline frailty and higher comorbidity profiles, patients with ASD who underwent corrective surgery with an ERAS protocol experienced fewer short-term adverse events and improved HRQL. We believe ERAS following ASD surgery leads to faster functional recovery, reduced postoperative deconditioning, and improved quality of life.

Comparison of Outcomes Between Staged and Same-Day Circumferential Spinal Fusion for Adult Spinal Deformity: Systematic Review and Meta-Analysis

BACKGROUND

Adult spinal deformity (ASD) is a prevalent condition often treated with circumferential spinal fusion (CF), which can be performed as staged or same-day procedures. However, evidence guiding the choice between these approaches is lacking.

OBJECTIVE

This study aims to compare patient outcomes following staged and same-day CF for ASD.

METHODS

Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a comprehensive literature search was conducted in PubMed, MEDLINE, Embase, Cochrane CENTRAL, Web of Science, and Scopus. Eligibility criteria included studies comparing outcomes following staged and same-day CF in adults with ASD. Searches were exported to Covidence, and records were deduplicated automatically. Title and abstract screening, full-text review, and data extraction were performed by two independent reviewers, with all conflicts being resolved by a third reviewer. A meta-analysis was conducted for outcomes reported in 3 or more studies.

RESULTS

Seven studies with 741 patients undergoing CF for ASD were included in the review (staged: n=331, 44.7% and same-day: n=410, 55.3%). Four studies that had comparable outcomes were merged for the quantitative meta-analysis and split based on observed measures. The meta-analysis revealed significantly shorter hospital length of stay (mean difference 3.98, 95% CI 2.23-5.72 days; P<.001) for same-day CF. Three studies compared the operative time between staged and same-day CF, with all reporting a lower mean operative time for same-day CF (mean between 291-479, SD 129 minutes) compared to staged CF (mean between 426-541, SD 124 minutes); however, inconsistent reporting of mean and SD made quantitative analyses unattainable. Of the 4 studies that compared estimated blood loss (EBL) in the relevant groups, 3 presented a lower EBL (mean between 412-1127, SD 954 mL) in same-day surgery compared to staged surgery (mean between 642, SD 550 to 1351, SD 869 mL). Both studies that reported intra- and postoperative adverse events showed more intraoperative adverse events in staged CF (10.9% and 13.6%, respectively) compared to same-day CF (9.1% and 3.6%, respectively). Four studies measuring any perioperative adverse events showed a higher incidence of adverse events in staged CF than all studies combined. However, quantitative analysis of EBL, intraoperative adverse events, and perioperative adverse events found no statistically significant difference. Postoperative adverse events, reoperation, infection rates, and readmission rates showed inconsistent findings between studies. Data quality assessment revealed a moderate degree of bias for all included studies.

CONCLUSIONS

Same-day CF may offer shorter operating time and hospital stay compared to staged CF for ASD. However, there was marked heterogeneity in perioperative outcomes reporting, and continuous variables were inconsistently presented. This underscored the need for standardized reporting of clinical variables and patient-reported outcomes and higher evidence of randomized controlled trials to elucidate the clinical superiority of either approach.

TRIAL REGISTRATION

PROSPERO CRD42022339764; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=339764.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.2196/42331.

Analysis of the factors associated with sexual health improvement in patients who underwent surgical management for adult spine deformity

BACKGROUND

Spinal deformity can have a severe impact on the patient's sexual health. Eventually, this can lead to depression and relationship distress. Spinal surgical management is suggested to improve sexual function, however, the literature concerning these aspects is still scarce. This study evaluated which factors predicted improvement in sexual health in patients with adult spinal deformity (ASD) who underwent surgical treatment.

METHODS

Multicentric retrospective study based on a prospectively collected ASD database. Data of patients who underwent surgical correction and had a 2-year follow-up were collected. The association between different patient-reported outcome measures and ODI question 8 (Q8, sexual health) was explored with Pearson correlations and Principal Component Analysis (PCA). Improvement in sexual health was evaluated through a 1-point decrease on Q8. Comparisons between improved and non-improved patients and the non-response to the preoperative Q8 were assessed.

RESULTS

Data from 880 patients were collected. Moderate correlations were revealed between ODI and COMI-back, SRS-22, and SF-36 items and confirmed with PCA. The main factors associated to a non-response to Q8 were being of an older age, having worse sagittal imbalance, and having a specific nationality. Patients with an improvement in sexual health at 2 years were the ones with a worse baseline quality of life, older patients with a greater sagittal correction, and a better improvement of the level of physical activity.

CONCLUSION

Non-response to Q8 was correlated to age and nationality. Long-segment ASD surgery could improve sexual health, which was correlated to physical activity improvement, severe deformity with worse preoperative quality of life, and better postoperative sagittal correction.

Impact of Paraspinal Muscle Degeneration on Surgical Outcomes and Radiographical Sagittal Alignment in Adult Spinal Deformity: A Multicenter Study

OBJECTIVE

This multicenter study aimed to evaluate the impact of paravertebral muscles (PVMs) degeneration, particularly fat infiltration, on preoperative sagittal imbalance, and postoperative complications and sagittal alignment change in patients with adult spinal deformity (ASD).

METHODS

A retrospective analysis was conducted on 454 patients who underwent ASD surgery across 5 institutions. Patients were classified into 2 groups based on paraspinal muscle fat infiltration on MRI: those with significant infiltration (FI-PVM(+)) and those with minimal or no infiltration (FI-PVM(-)). Propensity score matching was performed to adjust for demographic factors and preoperative radiographical parameters. Spinopelvic parameters were assessed preoperatively, postoperatively, and at a 2-year follow-up. Mechanical complications were compared between the groups.

RESULTS

The FI-PVM(+) group showed greater sagittal vertical axis (86.4 ± 57.5 vs. 51.8 ± 59.2, p < 0.001) preoperatively and required more extensive surgical correction with a significantly greater number of fused vertebral levels (7.3 ± 3.7 vs. 6.7 ± 3.7, p < 0.039). After propensity score matching, both groups showed significant improvement in spinopelvic alignment postoperatively, maintained throughout the 2-year follow-up. However, the FI-PVM(+) group demonstrated a trend toward a higher incidence of distal junctional kyphosis (6.3% vs. 0.9%, p = 0.070) and exhibited significantly greater decrease in pelvic tilt postoperatively (4.3° ± 7.6° vs. 1.3° ± 8.2°, p = 0.006).

CONCLUSION

Fat infiltration in PVM is associated with increased surgical complexity and a higher risk of mechanical complications. Preoperative assessment of muscle quality, along with targeted rehabilitation and closer postoperative monitoring, may be crucial for improving long-term outcomes in ASD surgery.

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.

Evaluating variability in decision-making among spine surgeons treating adult spine deformity

BACKGROUND CONTEXT

Significant variability in the management of Adult Spinal Deformity (ASD) has been observed among spine surgeons worldwide. The variability among Canadian spine surgeons, a country with universal public healthcare, remains unknown.

PURPOSE

The study aims to evaluate areas of variability in the perioperative optimization and surgical management of ASD among Canadian spine surgeons.

STUDY DESIGN/SETTING

In this cross-sectional study, 25 Canadian spine surgeons, predominantly orthopedic surgeons (20) and neurosurgeons (5) with varying experience, participated in an online survey focused on Adult Spinal Deformity (ASD).

SAMPLE

The study involved 25 Canadian spine surgeons with varying level of experience, representing both orthopedic and neurosurgical specialities.

OUTCOME MEASURE

The study aimed to evaluate the variability in surgical decision-making and perioperative optimization strategies among Canadian spine surgeons when faced with simulated scenarios of ASD pathologies.

METHODS

The online survey presented 4 vignettes with simulated scenarios of the most common ASD pathologies, including High Grade Spondylolisthesis (HGS), Neglected Adolescent Idiopathic Scoliosis (NAIS), Degenerative Scoliosis (DS), and Flat Back Syndrome (FBS). Questions in the vignettes explored ASD surgical decision-making, while additional questions focused on perioperative optimization. Descriptive statistics were used to analyze multiple-choice responses, and open-text responses were categorized into themes.

RESULTS

Variability was observed in the duration conservative treatment across the 4 ASD cases. Surgeons exhibited variability in the use of preoperative osteoporosis treatment. There was varied use of a dedicated anesthesiology team. Surgical goals varied in HGS and NAIS. The primary surgical method was variable in DS and HGS, the type of osteotomy varied in DS and FBS, and level of fixation varied in HGS and NAIS. Consensus was observed in the use of intraoperative monitoring across of all 4 ASD pathologies, the implementation of a team-based approach, and the selection of the primary surgical goal in DS and FBS.

CONCLUSION

Our cross-sectional study revealed variability among Canadian spine surgeons in the management of ASD, potentially influenced by the uncertain ASD progression, the need for evidence-based nonsurgical guidelines, and insufficient evidence on optimal surgical approaches. These findings will help guide future research to ultimately reduce variability and improve ASD patient management and outcomes.

Comparison of clinical and radiological outcomes of three-column lumbar osteotomies with and without interbody cages for adult spinal deformity

BACKGROUND CONTEXT

Correcting sagittal malalignment in adult spinal deformity (ASD) is a challenging task, often requiring complex surgical interventions like pedicle subtraction osteotomies (PSOs). Different types of three-column osteotomies (3COs), including Schwab 3, Schwab 4, Schwab 4 with interbody cages, and the "sandwich" technique, aim to optimize alignment and fusion outcomes. The role of interbody cages in enhancing fusion and segmental correction remains unclear.

PURPOSE

This study aimed to compare outcomes among these 4 3CO techniques, evaluating the impact of cage use at the osteotomy site on postoperative radiographic imaging and clinical outcomes.

STUDY DESIGN/SETTING

This is a multicenter retrospective study utilizing data from a prospective multicenter database of patients undergoing complex ASD surgery.

PATIENT SAMPLE

Ninety-seven patients who underwent 1 of 4 3CO techniques for thoracolumbar ASD correction with at least 2 years of follow-up were included. The sample consisted of 29 patients who underwent Schwab 3 osteotomy, 20 Schwab 4, 28 Schwab 4 with interbody cages, and 20 who underwent "sandwich" osteotomy.

OUTCOME MEASURES

The Scoliosis Research Society-22 revised (SRS22r) questionnaire evaluating pain, activity, appearance, mental health, and satisfaction was used to evaluate patient reported outcomes and radiographic measures including segmental lordosis and fusion rates determined by 3 blinded reviewers were used to evaluate physiologic outcomes.

METHODS

This study analyzed demographic data, radiographic outcomes, patient-reported outcomes, complications, and fusion rates over a 2-year follow-up period. Fusion status was determined via serial radiographs and evaluated independently by 3 blinded reviewers. Univariate and multivariate statistical analyses were performed to assess differences among the groups and the impact of interbody cage use on outcomes.

RESULTS

Patients undergoing "sandwich" osteotomy exhibited worse preoperative leg pain scores and lower SRS22r activity (p=.015), appearance (p=.007), and mental health domain scores (p=.0015). No differences in complications were found among groups (p>.05). Patients who underwent osteotomy with a cage were more likely to have had previous spine fusion (91.7% vs. 71.4%, p=.010). Additionally, these patients had lower preoperative SRS22r mental domain (2.9±1 vs. 3.5±1, p=.009), satisfaction (2.3±1 vs. 2.7±1.2, p=.034), and SRS22r total scores (2.3±0.6 vs. 2.6±0.6, p=.0026) but demonstrated the greatest improvement in the mental health domain (0.9±0.7 vs. 0.3±0.9, p=.002). Cage use was associated with a larger mean change in segmental lordosis at the osteotomy site (32.9±9.6 vs. 28.7±9.5, p=.038). Fusion rates were significantly higher in the cage group (79.2% vs. 55.1%, p=.0012). Regression analysis identified cage use as an independent predictor for fusion (odds ratio, 3.338; 95% confidence interval, 1.108-10.054, p=.032).

CONCLUSIONS

Interbody cage use at the osteotomy site during 3COs for ASD correction was associated with improved fusion rates and greater segmental lordosis without increasing complication rates. Incorporating cages may provide enhanced alignment and fusion outcomes in complex ASD surgeries.

Restoring L4-S1 Lordosis Shape in Severe Sagittal Deformity: Impact of Correction Techniques on Alignment and Complication Profile

BACKGROUND

Severe sagittal plane deformity with loss of L4-S1 lordosis is disabling and can be improved through various surgical techniques. However, data are limited on the differing ability of anterior lumbar interbody fusion (ALIF), pedicle subtraction osteotomy (PSO), and transforaminal lumbar interbody fusion (TLIF) to achieve alignment goals in severely malaligned patients.

METHODS

Severe adult spinal deformity patients with preoperative PI-LL >20°, L4-S1 lordosis <30°, and full body radiographs and PROMs at baseline and 6-week postoperative visit were included. Patients were grouped into ALIF (1-2 level ALIF at L4-S1), PSO (L4/L5 PSO), and TLIF (1-2 level TLIF at L4-S1). Comparative analyses were performed on demographics, radiographic spinopelvic parameters, complications, and PROMs.

RESULTS

Among the 96 included patients, 40 underwent ALIF, 27 underwent PSO, and 29 underwent TLIF. At baseline, cohorts had comparable age, sex, race, Edmonton frailty scores, and radiographic spinopelvic parameters (P > 0.05). However, PSO was performed more often in revision cases (P < 0.001). Following surgery, L4-S1 lordosis correction (P = 0.001) was comparable among ALIF and PSO patients and caudal lordotic apex migration (P = 0.044) was highest among ALIF patients. PSO patients had higher intraoperative estimated blood loss (P < 0.001) and motor deficits (P = 0.049), and in-hospital ICU admission (P = 0.022) and blood products given (P = 0.004), but were otherwise comparable in terms of length of stay, blood transfusion given, and postoperative admission to rehab. Likewise, 90-day postoperative complication profiles and 6-week PROMs were comparable as well.

CONCLUSIONS

ALIF can restore L4-S1 sagittal alignment as powerfully as PSO, with fewer intraoperative and in-hospital complications. When feasible, ALIF is a suitable alternative to PSO and likely superior to TLIF for correcting L4-S1 lordosis among patients with severe sagittal malalignment.

Radiographic Alignment in Deformity Patients Treated With Personalized Interbody Devices: Early Experience From the COMPASS Registry

BACKGROUND

Literature supports the need for improved techniques to achieve spinopelvic alignment and reduce complication rates in patients with adult spinal deformity (ASD). Personalized interbody devices were developed to address this need and are under evaluation in the multicenter Clinical Outcome Measures in Personalized aprevo (circle R superscript) Spine Surgery (COMPASS (TM suprascript) registry. This report presents interim COMPASS pre- and postoperative sagittal alignment results and complication rates for a subcohort of COMPASS patients diagnosed and surgically treated for spinal deformity.

METHODS

COMPASS is a postmarket observational registry of patients enrolled either before or after index surgery and then followed prospectively for 24 months. Sagittal alignment was assessed with SRS-Schwab modifiers for pelvic incidence minus lumbar lordosis, pelvic tilt, and T1 pelvic angle. Summed SRS-Schwab modifiers were utilized to assign overall deformity status as mild, moderate, or severe. Complications were extracted from patient medical records.

RESULTS

The study included 67 patients from 9 centers. Preoperative severe deformity was observed in 66% of patients. Index surgeries included implantation of a median of 2 personalized interbody devices by anterior, lateral, or transforaminal approaches and with a median of 8 posteriorly instrumented levels. Overall postoperative sagittal alignment improved with a significant decrease in the mean sum of SRS-Schwab modifiers that correlated strongly to improvements in pelvic incidence minus lumbar lordosis. Among 44 patients with preoperative severe overall deformity, 16 improved to moderate and 9 to mild deformity. Complications occurred for 13 patients (19.4%), including 1 mechanical complication requiring revision 9 months after surgery and none related to personalized interbody devices.

CONCLUSIONS

This study demonstrates that ASD patients whose treatment included personalized interbody devices can obtain favorable postoperative alignment status comparable to published results and with no complications related to the personalized interbody devices.

CLINICAL RELEVANCE

This study contributes to growing evidence that personalized interbody devices contribute to improved sagittal alignment in ASD patients by directly adjusting the orientation of adjacent vertebra.

LEVEL OF EVIDENCE: 3

Patient-Specific Rods in Adolescent and Adult Spinal Deformity Surgery: A Narrative Review

Spinal deformity surgery often requires complex surgical interventions that can have a drastic effect on both patient quality of life and functional capacity. Modern-day corrective solutions for these deformities include spinal osteotomies, pedicle screw instrumentation, and dual/multirod constructs. These solutions are efficacious and are currently considered standard practice for spinal surgeons, but they lack individualization. Patient-specific rods (PSRs) are a novel technology that attempts to offer a personalized approach to spinal deformity correction based on preoperative computerized tomography scans. Moreover, PSRs may offer several advantages to conventional rods, which include achievement of desired rod contour angles according to surgical planning alignment goals, reduced operative time, and reduced blood loss. In adolescent idiopathic scoliosis, those instrumented with PSR have observed coronal Cobb reductions up to 74%. In adult spinal deformity, PSRs have offered superior correction in radiographic parameters such as sagittal vertical axis and pelvic incidence minus lumbar lordosis. However, there still remains a paucity of research in this area, mainly in health care expenditure, cost-effectiveness, and longitudinal clinical outcomes. The purpose of this article is to survey the current body of knowledge of PSR instrumentation in both adolescent and adult spinal deformity populations. The current strength, limitations, and future directions of PSRs are highlighted throughout this article.

Spinal cord injury in high-risk complex adult spinal deformity surgery: review of incidence and outcomes from the Scoli-RISK-1 study

STUDY DESIGN

Clinical case series.

OBJECTIVE

To describe the cause, treatment and outcome of 6 cases of perioperative spinal cord injury (SCI) in high-risk adult deformity surgery.

SETTING

Adult spinal deformity patients were enrolled in the multi-center Scoli-RISK-1 cohort study.

METHODS

A total of 272 patients who underwent complex adult deformity surgery were enrolled in the prospective, multi-center Scoli-RISK-1 cohort study. Clinical follow up data were available up to a maximum of 2 years after index surgery. Cases of perioperative SCI were identified and an extensive case review was performed.

RESULTS

Six individuals with SCI were identified from the Scoli-RISK-1 database (2.2%). Two cases occurred intraoperatively and four cases occurred postoperatively. The first case was an incomplete SCI due to a direct intraoperative insult and was treated postoperatively with Riluzole. The second SCI case was caused by a compression injury due to overcorrection of the deformity. Three cases of incomplete SCI occurred; one case of postoperative hematoma, one case of proximal junctional kyphosis (PJK) and one case of adjacent segment disc herniation. All cases of post-operative incomplete SCI were managed with revision decompression and resulted in excellent clinical recovery. One case of incomplete SCI resulted from infection and PJK. The patient's treatment was complicated by a delay in revision and the patient suffered persistent neurological deficits up to six weeks following the onset of SCI.

CONCLUSION

Despite the low incidence in high-risk adult deformity surgeries, perioperative SCI can result in devastating consequences. Thus, appropriate postoperative care, follow up and timely management of SCI are essential.

Patient-specific rods in adult spinal deformity: a systematic review

PURPOSE

The purpose of this review was to evaluate the effectiveness of patient-specific rods for adult spinal deformity.

METHODS

A systematic review of the literature was performed through an electronic search of the PubMed, Scopus, and Web of Science databases. Human studies between 2012 and 2023 were included. Sample size, sagittal vertical axis (SVA), pelvic incidence-lumbar lordosis (PI-LL), pelvic tilt (PT), operation time, blood loss, follow-up duration, and complications were recorded for each study when available.

RESULTS

Seven studies with a total of 304 adult spinal deformity patients of various etiologies were included. All studies reported SVA, and PT; two studies did not report PI-LL. Four studies reported planned radiographic outcomes. Two found a significant association between preoperative plan and postoperative outcome in all three outcomes. One found a significant association for PI-LL alone. The fourth found no significant associations. SVA improved in six of seven studies, PI-LL improved in all five, and three of seven studies found improved postoperative PT. Significance of these results varied greatly by study.

CONCLUSION

Preliminary evidence suggests potential benefits of PSRs in achieving optimal spino-pelvic parameters in ASD surgery. Nevertheless, conclusions regarding the superiority of PSRs over traditional rods must be judiciously drawn, given the heterogeneity of patients and study methodologies, potential confounding variables, and the absence of robust randomized controlled trials. Future investigations should concentrate on enhancing preoperative planning, standardizing surgical methodologies, isolating specific patient subgroups, and head-to-head comparisons with traditional rods to fully elucidate the impact of PSRs in ASD surgery.

Who Can Be Discharged Home after Adult Spinal Deformity Surgery?

Introduction: After adult spinal deformity (ASD) surgery, patients often require postoperative rehabilitation at an inpatient rehabilitation (IPR) center or a skilled nursing facility (SNF). However, home discharge is often preferred by patients and hsas been shown to decrease costs. In a cohort of patients undergoing ASD surgery, we sought to (1) report the incidence of discharge to home, (2) determine the factors significantly associated with discharge to home in the form of a simple scoring system, and (3) evaluate the impact of discharge disposition on patient-reported outcome measures (PROMs). Methods: A single-institution, retrospective cohort study was undertaken for patients undergoing ASD surgery from 2009 to 2021. Inclusion criteria were ≥ 5-level fusion, sagittal/coronal deformity, and at least 2-year follow-up. Exposure variables included preoperative, perioperative, and radiographic data. The primary outcome was discharge status (dichotomized as home vs. IPR/SNF). Secondary outcomes included PROMs, such as the numeric rating scales (NRSs) for back and leg pain, the Oswestry Disability Index (ODI), and EQ-5D. A subanalysis comparing IPR to SNF discharge was conducted. Univariate analysis was performed. Results: Of 221 patients undergoing ASD surgery with a mean age of 63.6 ± 17.6, 112 (50.6%) were discharged home, 71 (32.2%) were discharged to an IPR center, and 38 (17.2%) were discharged to an SNF. Patients discharged home were significantly younger (55.7 ± 20.1 vs. 71.8 ± 9.1, p < 0.001), had lower rate of 2+ comorbidities (38.4% vs. 45.0%, p = 0.001), and had less hypertension (57.1% vs. 75.2%, p = 0.005). Perioperatively, patients who were discharged home had significantly fewer levels instrumented (10.0 ± 3.0 vs. 11.0 ± 3.4 levels, p = 0.030), shorter operative times (381.4 ± 139.9 vs. 461.6 ± 149.8 mins, p < 0.001), less blood loss (1101.0 ± 977.8 vs. 1739.7 ± 1332.9 mL, p < 0.001), and shorter length of stay (5.4 ± 2.8 vs. 9.3 ± 13.9 days, p < 0.001). Radiographically, preoperative SVA (9.1 ± 6.5 vs. 5.2 ± 6.8 cm, p < 0.001), PT (27.5 ± 11.1° vs. 23.4 ± 10.8°, p = 0.031), and T1PA (28.9 ± 12.7° vs. 21.6 ± 13.6°, p < 0.001) were significantly higher in patients who were discharged to an IPR center/SNF. Additionally, the operating surgeon also significantly influenced the disposition status (p < 0.001). A scoring system of the listed factors was proposed and was validated using univariate logistic regression (OR = 1.55, 95%CI = 1.34-1.78, p < 0.001) and ROC analysis, which revealed a cutoff value of > 6 points as a predictor of non-home discharge (AUC = 0.75, 95%CI = 0.68-0.80, p < 0.001, sensitivity = 63.3%, specificity = 74.1%). The factors in the scoring system were age > 56, comorbidities ≥ 2, hypertension, TIL ≥ 10, operative time > 357 mins, EBL > 1200 mL, preop SVA > 6.6 cm, preop PT > 33.6°, and preop T1PA > 15°. When comparing IPR (n = 71) vs. SNF (n = 38), patients discharged to an SNF were significantly older (74.4 ± 8.6 vs. 70.4 ± 9.1, p = 0.029) and were more likely to be female (89.5% vs. 70.4%, p = 0.024). Conclusions: Approximately 50% of patients were discharged home after ASD surgery. A simple scoring system based on age > 56, comorbidities ≥ 2, hypertension, total instrumented levels ≥ 10, operative time > 357 mins, EBL > 1200 mL, preop SVA > 6.6 cm, preop PT > 33.6°, and preop T1PA > 15° was proposed to predict non-home discharge. These findings may help guide postoperative expectations and resource allocation after ASD surgery.

Evaluating Computer Vision, Large Language, and Genome-Wide Association Models in a Limited Sized Patient Cohort for Pre-Operative Risk Stratification in Adult Spinal Deformity Surgery

Background: Adult spinal deformities (ASD) are varied spinal abnormalities, often necessitating surgical intervention when associated with pain, worsening deformity, or worsening function. Predicting post-operative complications and revision surgery is critical for surgical planning and patient counseling. Due to the relatively small number of cases of ASD surgery, machine learning applications have been limited to traditional models (e.g., logistic regression or standard neural networks) and coarse clinical variables. We present the novel application of advanced models (CNN, LLM, GWAS) using complex data types (radiographs, clinical notes, genomics) for ASD outcome prediction. Methods: We developed a CNN trained on 209 ASD patients (1549 radiographs) from the Stanford Research Repository, a CNN pre-trained on VinDr-SpineXR (10,468 spine radiographs), and an LLM using free-text clinical notes from the same 209 patients, trained via Gatortron. Additionally, we conducted a GWAS using the UK Biobank, contrasting 540 surgical ASD patients with 7355 non-surgical ASD patients. Results: The LLM notably outperformed the CNN in predicting pulmonary complications (F1: 0.545 vs. 0.2881), neurological complications (F1: 0.250 vs. 0.224), and sepsis (F1: 0.382 vs. 0.132). The pre-trained CNN showed improved sepsis prediction (AUC: 0.638 vs. 0.534) but reduced performance for neurological complication prediction (AUC: 0.545 vs. 0.619). The LLM demonstrated high specificity (0.946) and positive predictive value (0.467) for neurological complications. The GWAS identified 21 significant (p < 10-5) SNPs associated with ASD surgery risk (OR: mean: 3.17, SD: 1.92, median: 2.78), with the highest odds ratio (8.06) for the LDB2 gene, which is implicated in ectoderm differentiation. Conclusions: This study exemplifies the innovative application of cutting-edge models to forecast outcomes in ASD, underscoring the utility of complex data in outcome prediction for neurosurgical conditions. It demonstrates the promise of genetic models when identifying surgical risks and supports the integration of complex machine learning tools for informed surgical decision-making in ASD.

External Validation of the Global Alignment and Proportion Score as Prognostic Tool for Corrective Surgery in Adult Spinal Deformity: A Systematic Review and Meta-Analysis

BACKGROUND

Since its proposal, the Global Alignment and Proportion (GAP) score has been the topic of several external validation studies, which have yielded conflicting results. Given the lack of consensus regarding this prognostic tool, the authors aim to assess the accuracy of GAP scores for predicting mechanical complications following adult spinal deformity correction surgery.

METHODS

A systematic search was performed using PubMed, Embase, and Cochrane Library for the purpose of identifying all studies evaluating the GAP score as a predictive tool for mechanical complications. GAP scores were pooled using a random-effects model to compare patients reporting mechanical complications after surgery versus those reporting no complications. Where receiver operator curves were provided, the area under the curve (AUC) was pooled.

RESULTS

A total of 15 studies featuring 2092 patients were selected for inclusion. Qualitative analysis using Newcastle-Ottawa criteria revealed moderate quality among all included studies (5.99/9). With respect to sex, the cohort was predominantly female (82%). The pooled mean age among all patients in the cohort was 58.55 years, with a mean follow-up of 33.86 months after surgery. Upon pooled analysis, we found that mechanical complications were associated with higher mean GAP scores, albeit minimal (mean difference = 0.571 [ 95% confidence interval: 0.163-0.979]; P = 0.006, n = 864). Additionally, age (P = 0.136, n = 202), fusion levels (P = 0.207, n = 358), and body mass index (P = 0.616, n = 350) were unassociated with mechanical complications. Pooled AUC revealed poor discrimination overall (AUC = 0.69; n = 1206).

CONCLUSIONS

GAP scores may have a minimal-to-moderate predictive capability for mechanical complications associated with adult spinal deformity correction.

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.

Patient-Reported Outcomes After Complex Adult Spinal Deformity Surgery: 5-Year Results of the Scoli-Risk-1 Study

STUDY DESIGN

Prospective cohort.

OBJECTIVE

To prospectively evaluate PROs up to 5-years after complex ASD surgery.

METHODS

The Scoli-RISK-1 study enrolled 272 ASD patients undergoing surgery from 15 centers. Inclusion criteria was Cobb angle of >80°, corrective osteotomy for congenital or revision deformity, and/or 3-column osteotomy. The following PROs were measured prospectively at intervals up to 5-years postoperative: ODI, SF36-PCS/MCS, SRS-22, NRS back/leg. Among patients with 5-year follow-up, comparisons were made from both baseline and 2-years postoperative to 5-years postoperative. PROs were analyzed using mixed models for repeated measures.

RESULTS

Seventy-seven patients (28.3%) had 5-year follow-up data. Comparing baseline to 5-year data among these 77 patients, significant improvement was seen in all PROs: ODI (45.2 vs. 29.3, P < 0.001), SF36-PCS (31.5 vs. 38.8, P < 0.001), SF36-MCS (44.9 vs. 49.1, P = 0.009), SRS-22-total (2.78 vs. 3.61, P < 0.001), NRS-back pain (5.70 vs. 2.95, P < 0.001) and NRS leg pain (3.64 vs. 2.62, P = 0.017). In the 2 to 5-year follow-up period, no significant changes were seen in any PROs. The percentage of patients achieving MCID from baseline to 5-years were: ODI (62.0%) and the SRS-22r domains of function (70.4%), pain (63.0%), mental health (37.5%), self-image (60.3%), and total (60.3%). Surprisingly, mean values (P > 0.05) and proportion achieving MCID did not differ significantly in patients with major surgery-related complications compared to those without.

CONCLUSIONS

After complex ASD surgery, significant improvement in PROs were seen at 5-years postoperative in ODI, SF36-PCS/MCS, SRS-22r, and NRS-back/leg pain. No significant changes in PROs occurred during the 2 to 5-year postoperative period. Those with major surgery-related complications had similar PROs and proportion of patients achieving MCID as those without these complications.

The Function Assessment Scale for Spinal Deformity: Validity and Reliability of a New Clinical Scale

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

The aim of this study was to develop and validate the Function Assessment scale for Spinal Deformity (FASD).

SUMMARY OF BACKGROUND DATA

Spinal malalignment impacts daily functioning. Standard evaluation of adult spinal deformity (ASD) is based on static radiography and patient-reported scores, which fail to assess functional impairments. A clinical scale, quantifying function and balance of patients with ASD, could increase our insights on the impact of ASD on functioning.

METHODS

To develop the FASD, 70 ASD patients and 20 controls were measured to identify the most discriminating items of the Balance Evaluation Systems Test and Trunk Control Measurement Scale. Discussions between experts on the clinical relevance of selected items led to further item reduction. The FASD's discriminative ability was established between 43 patients and 19 controls, as well as between three deformity subgroups. For its responsiveness to treatment, 10 patients were reevaluated 6 months postoperatively. Concurrent validity was assessed through correlation analysis with radiographic parameters (pelvic tilt; sagittal vertical axis [SVA]; pelvic incidence minus lumbar lordosis [PI-LL]; coronal vertical axis) and patient-reported scores [Oswestry Disability Index]; Scoliosis Research Society outcome questionnaire; Falls Efficacy Scale-International). Test-retest and interrater reliability were tested on two groups of ten patients using intraclass correlation coefficients (ICC).

RESULTS

Patients with ASD, mainly with sagittal malalignment, scored worse compared to controls on FASD (P < 0.001) and its subscales. No significant improvement was observed 6 months postoperatively (P = 0.758). FASD correlated significantly to all patient-reported scores and to SVA and PI-LL. Reliability between sessions (ICC = 0.97) and raters (ICC = 0.93) was excellent. Subscales also showed good to excellent reliability, except FASD 1 on "spinal mobility and balance" between sessions (ICC = 0.71).

CONCLUSION

FASD proved to be a valid and reliable clinical scale for evaluation of functional impairments in ASD. Objective information on function and balance might ultimately guide physiotherapeutic treatment toward improved functioning.Level of Evidence: 2.

The Scoli-RISK 1 results of lower extremity motor function 5 years after complex adult spinal deformity surgery

INTRODUCTION

Neurologic complications after complex adult spinal deformity (ASD) surgery are important, yet outcomes are heterogeneously reported, and long-term follow-up of actual lower extremity motor function is unknown.

OBJECTIVE

To prospectively evaluate lower extremity motor function scores (LEMS) before and at 5 years after surgical correction of complex ASD.

DESIGN

Retrospective analysis of a prospective, multicenter, international observational study.

METHODS

The Scoli-RISK-1 study enrolled 272 ASD patients undergoing surgery from 15 centers around the world. Inclusion criteria were Cobb angle of > 80°, corrective osteotomy for congenital or revision deformity and/or 3-column osteotomy. Among patients with 5-year follow-up, comparisons of LEMS to baseline and within each follow-up period were made via documented neurologic exams on each patient.

RESULTS

Seventy-seven (28.3%) patients had 5-year follow-up. Among these 77 patients with 5-year follow-up, rates of postoperative LEMS deterioration were: 14.3% hospital discharge, 10.7% at 6 weeks, 6.5% at 6 months, 9.5% at 2 years and 9.3% at 5 years postoperative. During the 2-5 year window, while mean LEMS did not change significantly (-0.5, p = 0.442), eight (11.1%) patients deteriorated (of which 3 were ≥ 4 motor points), and six (8.3%) patients improved (of which 2 were ≥ 4 points). Of the 14 neurologic complications, four (28.6%) were surgery-related, three of which required reoperation. While mean LEMS were not impacted in patients with a major surgery-related complication, mean LEMS were significantly lower in patients with neurologic surgery-related complications at discharge (p = 0.041) and 6 months (p = 0.008) between the two groups as well as the change from baseline to 5 years (p = 0.041).

CONCLUSIONS

In 77 patients undergoing complex ASD surgery with 5-year follow-up, while mean LEMS did not change from 2 to 5 years, subtle neurologic changes occurred in approximately 1 in 5 patients (11.1% deteriorated; 8.3% improved). Major surgery-related complication did not result in decreased LEMS; however, those with neurologic surgery-related complications continued to have decreased lower extremity motor function at 5 years postoperative. These results underscore the importance of long-term follow-up to 5 years, using individual motor scores rather than group averages, and comparing outcomes to both baseline and last follow-up.

Impact of New Motor Deficit on HRQOL After Adult Spinal Deformity Surgery: Subanalysis From Scoli Risk 1 Prospective Study

STUDY DESIGN

International, multicenter, prospective, longitudinal observational cohort.

OBJECTIVE

To assess how new motor deficits affect patient reported quality of life scores after adult deformity surgery.

SUMMARY OF BACKGROUND DATA

Adult spinal deformity surgery is associated with high morbidity, including risk of new postoperative motor deficit. It is unclear what effect new motor deficit has on Health-related Quality of Life scores (HRQOL) scores.

METHODS

Adult spinal deformity patients were enrolled prospectively at 15 sites worldwide. Other inclusion criteria included major Cobb more than 80°, C7-L2 curve apex, and any patient undergoing three column osteotomy. American Spinal Injury Association (ASIA) scores and standard HRQOL scores were recorded pre-op, 6 weeks, 6 months, and 2 years.

RESULTS

Two hundred seventy two complex adult spinal deformity (ASD) patients enrolled. HRQOL scores were worse for patients with lower extremity motor score (LEMS). Mean HRQOL changes at 6 weeks and 2 years compared with pre-op for patients with motor worsening were: ODI (+12.4 at 6 weeks and -4.7 at 2 years), SF-36v2 physical (-4.5 at 6 weeks and +2.3 at 2 years), SRS-22r (0.0 at 6 weeks and +0.4 at 2 years). Mean HRQOL changes for motor-neutral patients were: ODI (+0.6 at 6 weeks and -12.1 at 2 years), SF-36v2 physical (-1.6 at 6 weeks and +5.9 at 2 years), and SRS-22r (+0.4 at 6 weeks and +0.7 at 2 years). For patients with LEMS improvement, mean HRQOL changes were: ODI (-0.6 at 6 weeks and -16.3 at 2 years), SF-36v2 physical (+1.0 at 6 weeks and +7.0 at 2 years), and SRS-22r (+0.5 at 6 weeks and +0.9 at 2 years).

CONCLUSION

In the subgroup of deformity patients who developed a new motor deficit, total HRQOLs and HRQOL changes were negatively impacted. Patients with more than 2 points of LEMS worsening had the worst changes, but still showed overall HRQOL improvement at 6 months and 2 years compared with pre-op baseline.Level of Evidence: 3.

Are Higher Global Alignment and Proportion Scores Associated With Increased Risks of Mechanical Complications After Adult Spinal Deformity Surgery? An External Validation

BACKGROUND

The Global Alignment and Proportion (GAP) score, based on pelvic incidence-based proportional parameters, was recently developed to predict mechanical complications after surgery for spinal deformities in adults. However, this score has not been validated in an independent external dataset.

QUESTIONS/PURPOSES

After adult spinal deformity surgery, is a higher GAP score associated with (1) an increased risk of mechanical complications, defined as rod fractures, implant-related complications, proximal or distal junctional kyphosis or failure; (2) a higher likelihood of undergoing revision surgery to treat a mechanical complication; and (3) is a lower (more proportioned) GAP score category associated with better validated outcomes scores using the Oswestry Disability Index (ODI), Scoliosis Research Society-22 (SRS-22) and the Short Form-36 questionnaires?

METHODS

A total of 272 patients who had undergone corrective surgeries for complex spinal deformities were enrolled in the Scoli-RISK-1 prospective trial. Patients were included in this secondary analysis if they fulfilled the original inclusion criteria by Yilgor et al. From the original 272 patients, 14% (39) did not satisfy the radiographic inclusion criteria, the GAP score could not be calculated in 14% (37), and 24% (64) did not have radiographic assessment at postoperative 2 years, leaving 59% (159) for analysis in this review of data from the original trial. A total of 159 patients were included in this study,with a mean age of 58 ± 14 years at the time of surgery. Most patients were female (72%, 115 of 159), the mean number of levels involved in surgery was 12 ± 4, and three-column osteotomy was performed in 76% (120 of 159) of patients. The GAP score was calculated using parameters from early postoperative radiographs (between 3 and 12 weeks) including pelvic incidence, sacral slope, lumbar lordosis, lower arc lordosis and global tilt, which were independently obtained from a computer software based on centralized patient radiographs. The GAP score was categorized as proportional (scores of 0 to 2), moderately disproportional (scores of 3 to 6), or severely disproportional (scores higher than 7 to 13). Receiver operating characteristic area under curve (AUC) was used to assess associations between GAP score and risk of mechanical complications and risk of revision surgery. An AUC of 0.5 to 0.7 was classified as "no or low associative power", 0.7 to 0.9 as "moderate" and greater than 0.9 as "high". We analyzed differences in validated outcome scores between the GAP categories using Wilcoxon rank sum test.

RESULTS

At a minimum of 2 years' follow-up, a higher GAP score was not associated with increased risks of mechanical complications (AUC = 0.60 [95% CI 0.50 to 0.70]). A higher GAP score was not associated with a higher likelihood of undergoing a revision surgery to treat a mechanical complication (AUC = 0.66 [95% 0.53 to 0.78]). However, a moderately disproportioned GAP score category was associated with better SF-36 physical component summary score (36 ± 10 versus 40 ± 11; p = 0.047), better SF-36 mental component summary score (46 ± 13 versus 51 ± 12; p = 0.01), better SRS-22 total score (3.4 ± 0.8 versus 3.7 ± 0.7, p = 0.02) and better ODI score (35 ± 21 versus 25 ± 20; p = 0.003) than severely disproportioned GAP score category.

CONCLUSION

Based on the findings of this external validation study, we found that alignment targets based on the GAP score alone were not associated with increased risks of mechanical complications and mechanical revisions in patients with complex adult spinal disorders. Parameters not included in the original GAP score needed to be considered to reduce the likelihood of mechanical complications.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Revision strategies for failed adult spinal deformity surgery

PURPOSE

The aim of this study is to analyse the results of revision surgery for failed adult spinal deformity patients and to describe the surgical strategy selection process, based on the identification of the main clinical diagnosis responsible for failure.

METHODS

We retrospectively reviewed the clinical and radiological data of 77 consecutive patients treated in a 3-year time (2016-2019) for surgical revision of long fusion (more than five levels fused) for adult spinal deformity in a high-volume spine centre, divided into four groups based on the diagnosis: rod breakage (RB) group, proximal junctional failure (PJF) group, distal junctional failure (DJF) group and loss of correction (LOC) group with symptomatic sagittal or coronal malalignment (including iatrogenic flatback).

RESULTS

Seventy-seven patients met our inclusion criteria, with a female prevalence (66 F vs. 11 M). The mean age at revision surgery was 63. Fused levels before surgery were averagely 12, and revision added averagely two levels to the preexisting fusion area. Clinical status was apparently improved in ODI scores and VAS scores, while it was slightly worsened in SF36 scores. Different diagnosis groups have been addressed with different surgical strategies, according to the different surgical goals: interbody cages and multi-rod construct to improve stiffness and favour bony fusion, "kickstand" rod and "tie" rod to correct coronal and sagittal malalignment, specific rod contouring and proximal hooks in "claw" configuration to reduce mechanical stress at the proximal junctional area. Intraoperative complications occurred in 18% of patients and perioperative complications in 39%.

CONCLUSION

Revision surgery in long fusions for adult spinal deformity is a challenging field. Surgical strategy should always be planned carefully. A successful treatment is a direct consequence of a correct preoperative diagnosis, and surgery should address the primary cause of failure. All the above-mentioned surgical techniques and clinical skills should be part of surgeon's expertise when managing these patients. These slides can be retrieved under Electronic Supplementary Material.