Neurologic Outcomes of Complex Adult Spinal Deformity Surgery: Results of the Prospective, Multicenter Scoli-RISK-1 Study

The ISSG-AO Complication Intervention Score, but Not Major/Minor Designation, is Correlated With Length of Stay Following Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective review.

OBJECTIVES

The International Spine Study Group-AO (ISSG-AO) Adult Spinal Deformity (ASD) Complication Classification System was developed to improve classification, reporting, and study of complications among patients undergoing ASD surgery. The ISSG-AO system classifies interventions to address complications by level of invasiveness: grade zero (none); grade 1, mild (e.g., medication change); grade 2, moderate (e.g., ICU admission); grade 3, severe (e.g., reoperation related to surgery of interest). To evaluate the efficacy of the ISSG-AO ASD Complication Classification System, we aimed to compare correlations between postoperative length of stay (LOS) and complication severity as classified by the ISSG-AO ASD and traditional major/minor complication classification systems.

METHODS

Patients age ≥18 in a multicenter ASD database who sustained in-hospital complications were identified. Complications were classified with the major/minor and ISSG-AO systems and correlated with LOS using an ensemble-based machine learning algorithm (conditional random forest) and a generalized linear mixed model.

RESULTS

490 patients at 19 sites were included. 64.9% of complications were major, and 35.1% were minor. By ISSG-AO classification, 20.4%, 66.1%, 6.7%, and 6.7% were grades 0-3, respectively. ISSG-AO complication grading demonstrated significant correlation with LOS, whereas major/minor complication classification demonstrated inverse correlation with LOS. In conditional random forest analysis, ISSG-AO classification had the greatest relative importance when assessing correlations across multiple variables with LOS.

CONCLUSIONS

The ISSG-AO system may help identify specific complications associated with prolonged LOS. Targeted interventions to avoid or reduce these complications may improve ASD surgical quality and resource utilization.

Anterior Column Release: With Great Lordosis Comes Great Risk of Complications-A Case Series

STUDY DESIGN

Retrospective review.

OBJECTIVE

We sought to characterize complications associated with anterior column release (ACR).

SUMMARY OF BACKGROUND DATA

Correction of positive sagittal imbalance was traditionally completed with anterior column grafts or posterior osteotomies. ACR is a minimally invasive technique for addressing sagittal plane deformity by restoring lumbar lordosis.

METHODS

We conducted a retrospective review of consecutive patients who underwent ACR in a prospectively kept database at a tertiary care academic center from January 2012 to December 2018. The prespecified complications were hardware failure (rod fracture, hardware loosening, or screw fracture), proximal junctional kyphosis, ipsilateral thigh numbness, ipsilateral femoral nerve weakness, arterial injury requiring blood transfusion, bowel injury, and abdominal pseudohernia.

RESULTS

Thirty-eight patients were identified. Thirty-five patients had ACR at L3-4, 1 had ACR at L4-5, and 1 patient had ACR at L2-3 and L3-4. Eighteen patients (47.4%) had one of the prespecified complications (10 patients had multiple). Ten patients developed hardware failure (26.3%); 8 patients (21.1%) had rod fracture, 4 (10.5%) had screw fracture, and 1 (2.6%) had screw loosening. At discharge, rates of ipsilateral thigh numbness (37.8%) and hip flexor (37.8%)/quadriceps weakness (29.7%) were the highest. At follow-up, 6 patients (16.2%) had ipsilateral anterolateral thigh numbness, 5 (13.5%) suffered from ipsilateral hip flexion weakness, and 3 patients (5.4%) from ipsilateral quadriceps weakness. Arterial injury occurred in 1 patient (2.7%). Abdominal pseudohernia occurred in 1 patient (2.7%). There were no bowel injuries observed.

CONCLUSIONS

ACR is associated with a higher than initially anticipated risk of neurological complications, hardware failure, and proximal junctional kyphosis.

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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Does an improvement in cord-level intraoperative neuromonitoring data lead to a reduced risk for postoperative neurologic deficit in spine deformity surgery?

PURPOSE

To determine if an improvement in cord-level intraoperative neuromonitoring (IONM) data following data loss results in a reduced risk for new postoperative motor deficit in pediatric and adult spinal deformity surgery.

METHODS

A consecutive series of 1106 patients underwent spine surgery from 2015 to 2023 by a single surgeon. Cord alerts were defined by Somatosensory-Evoked Potentials (SSEP; warning criteria: 10% increase in latency or > 50% loss in amplitude) and Motor-Evoked Potentials (MEP; warning criteria: 75% loss in amplitude without return to acceptable limits after stimulation up 100 V above baseline level). Timing of IONM loss and recovery, interventions, and baseline/postoperative day 1 (POD1) lower extremity motor scores were analyzed.

RESULTS

IONM Cord loss was noted in 4.8% (53/11,06) of patients and 34% (18/53) with cord alerts had a POD1 deficit compared to preoperative motor exam. MEP and SSEP loss attributed to 98.1% (52/53) and 39.6% (21/53) of cord alerts, respectively. Abnormal descending neurogenic-evoked potential (DNEP) was seen in 85.7% (12/14) and detected 91.7% (11/12) with POD1 deficit. Abnormal wake-up test (WUT) was seen in 38.5% (5/13) and detected 100% (5/5) with POD1 deficit. Most cord alerts occurred during a three-column osteotomy (N = 23/53, 43%); decompression (N = 12), compression (N = 7), exposure (N = 4), and rod placement (N = 14). Interventions were performed in all 53 patients with cord loss and included removing rods/less correction (N = 11), increasing mean arterial pressure alone (N = 10), and further decompression with three-column osteotomy (N = 9). After intervention, IONM data improved in 45(84.9%) patients (Full improvement: N = 28; Partial improvement: 17). For those with full and partial IONM improvement, the POD1 deficit was 10.7% (3/28) and 41.2% (7/17), respectively. For those without any IONM improvement (15.1%, 8/53), 100% (8/8) had a POD1 deficit, P < 0.001.

CONCLUSION

A full or partial improvement in IONM data loss after intraoperative intervention was significantly associated with a lower risk for POD1 deficit with an absolute risk reduction of 89.3% and 58.8%, respectively. All patients without IONM improvement had a POD1 neurologic deficit.

A Novel Preoperative Scoring System to Accurately Predict Cord-Level Intraoperative Neuromonitoring Data Loss During Spinal Deformity Surgery: A Machine-Learning Approach

BACKGROUND

An accurate knowledge of a patient's risk of cord-level intraoperative neuromonitoring (IONM) data loss is important for an informed decision-making process prior to deformity correction, but no prediction tool currently exists.

METHODS

A total of 1,106 patients with spinal deformity and 205 perioperative variables were included. A stepwise machine-learning (ML) approach using random forest (RF) analysis and multivariable logistic regression was performed. Patients were randomly allocated to training (75% of patients) and testing (25% of patients) groups. Feature score weights were derived by rounding up the regression coefficients from the multivariable logistic regression model. Variables in the final scoring calculator were automatically selected through the ML process to optimize predictive performance.

RESULTS

Eight features were included in the scoring system: sagittal deformity angular ratio (sDAR) of ≥15 (score = 2), type-3 spinal cord shape (score = 2), conus level below L2 (score = 2), cervical upper instrumented vertebra (score = 2), preoperative upright largest thoracic Cobb angle of ≥75° (score = 2), preoperative lower-extremity motor deficit (score = 2), preoperative upright largest thoracic kyphosis of ≥80° (score = 1), and total deformity angular ratio (tDAR) of ≥25 (score = 1). Higher cumulative scores were associated with increased rates of cord-level IONM data loss: patients with a cumulative score of ≤2 had a cord-level IONM data loss rate of 0.9%, whereas those with a score of ≥7 had a loss rate of 86%. When evaluated in the testing group, the scoring system achieved an accuracy of 93%, a sensitivity of 75%, a specificity of 94%, and an AUC (area under the receiver operating characteristic curve) of 0.898.

CONCLUSIONS

This is the first study to provide an ML-derived preoperative scoring system that predicts cord-level IONM data loss during pediatric and adult spinal deformity surgery with >90% accuracy.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Revision of Harrington rod constructs: a single-center's experience with this homogenous adult spinal deformity population at a minimum 2-year follow-up

PURPOSE

To evaluate radiographic and clinical outcomes following revision surgery after HRC fusions.

METHODS

Single-institution, retrospective study of patients revised following HRC with minimum 2-year follow-up post-revision. Demographics, perioperative information, radiographic parameters, complications, and Oswestry disability index (ODI) scores were collected. Radiographic parameters included global alignment, coronal and sagittal measurements pre and postoperatively, as well as final follow-up time points.

RESULTS

26 patients were included with a mean follow-up of 3.3 ± 1.1 years. Mean age was 55.5 ± 7.8 years, BMI 25.2 ± 5.8, and 22 (85%) were females. Instrumented levels increased from 9.7 ± 2.8 to 16.0 ± 2.2. Five (19.2%) patients underwent lumbar pedicle subtraction osteotomies, and 23 (88.4%) had interbody fusions. Patients significantly improved in all radiographic parameters at immediate and final follow-up (p < 0.005), except for thoracic kyphosis and pelvic incidence (p > 0.05). Correction was maintained from immediate postop to final follow-up (p > 0.05). 20 (76.9%) of patients experienced a complication at some point within the follow-up period with the most common being a lumbar nerve root deficit (n = 7). However, only one patient had a nerve root deficit at final follow-up, that being a 4/5 unilateral anterior tibialis function. 5 (19.2%) patients required further revision within a mean of 1.8 ± 1.1 years. On average, patients had an improvement in ODI score by final follow-up (35.6 ± 16.8 vs 25.4 ± 19.8, p = 0.035).

CONCLUSION

Patients revised for HRCs significantly improve, both clinically and radiographically by final follow-up. This group did have a propensity for distal lumbar root neurological issues, which were common but all patients except for one, recovered to full strength by two-year follow-up.

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.

What Radiographic and Clinical Factors Ultimately Necessitate a C2-Sacrum Instrumented Posterior Spinal Fusion?

OBJECTIVE

/Hypothesis: Patients undergoing C2-sacrum PSF have unique medical histories and multiple prior operations over an extended period.

DESIGN

Single center, retrospective cohort.

METHODS

Consecutive C2-sacrum PSF patients operated on by 4 surgeons at a single-center from 2015-2020 were reviewed. Demographics, comorbidities, indications, surgical history, and radiographic parameters were collected.

RESULTS

23 patients underwent C2-sacrum PSF. 13 (57%) were male, and 21 (91.3%) were adults. Mean age at time of first spine surgery was 44 years (range 5-71) and 53 years (range 14-72) at the time of C2-sacrum PSF. Six patients (26%) had osteoporosis, and 6 patients (26%) had neurologic comorbidities-including Parkinson's disease (4), cerebral palsy (1), and Brown Sequard syndrome (1). Four (17%) had connective tissue disease. Two patients underwent C2-sacrum PSF as an index procedure: (1) 67M with myelomatous fractures and 124° of cervicothoracic kyphosis; (2) 28F with severe Marfan syndrome with 140° thoracic scoliosis and 130° thoracic kyphosis. The remaining 21 (91%) underwent C2-sacrum PSF as a revision following prior spinal surgeries on average, 4 previous surgeries (range 1-13) over 10.5 years (range .3-37.4). Indications for the remaining 21 C2-sacrum PSF revision procedures included 17 (81%) for kyphosis (5 of whom also had significant coronal deformity), 1 (5%) for only coronal malalignment, 2 (10%) for instrumentation failure, and 1 (5%) for myelopathy.

CONCLUSIONS

91% (21/23) of patients requiring C2-sacrum PSF were treated as revisions of prior fusions, with a mean of 4 prior surgeries over 10 years. Over 80% of these patients underwent C2-sacrum PSF to address kyphosis. 26% had neurologic conditions, and 26% had osteoporosis.

Prospective Validation of the Spinal Cord Shape Classification System in the Prediction of Intraoperative Neuromonitoring Data Loss: Assessing the Risk of Spinal Cord Data Loss During Spinal Deformity Correction

BACKGROUND

The Spinal Cord Shape Classification System (SCSCS) class has been associated with spinal cord monitoring data loss during spinal deformity surgery. The objective of the current study was to prospectively validate the SCSCS as a predictor of spinal cord monitoring data loss during spinal deformity surgery.

METHODS

A prospective cohort study of consecutive patients who were undergoing primary deformity surgery at a single institution from 2018 to 2023 and whose major curve was in the spinal cord region was undertaken. Spinal cord morphology at the apex of the major curve on preoperative axial T2-weighted magnetic resonance imaging was used to categorize patients into 3 spinal cord shape types based on the SCSCS. The primary outcome was intraoperative neuromonitoring (IONM) data loss related to spinal cord dysfunction. Demographics and surgical and radiographic variables were compared between patients with IONM data loss and those without loss. Predictors of IONM loss were determined using bivariate and multivariable logistic regression analyses.

RESULTS

A total of 256 patients (168 adult, 88 pediatric) were included and were separated into 3 SCSCS types: 110 (43.0%) with Type I, 105 (41.0%) with Type II, and 41 (16.0%) with Type III. IONM loss was observed in 30 (11.7%) of the 256 patients, including 7 (6.4%) of 110 with SCSCS Type I, 7 (6.7%) of 105 with Type II, and 16 (39.0%) of 41 with Type III. IONM loss was associated with SCSCS Type III, the preoperative deformity angular ratio, performance of 3-column osteotomies, greater operative time, greater transfusion volume, and greater postoperative sagittal corrections. SCSCS type was the strongest independent predictor of IONM data loss. SCSCS Type III had the greatest odds of IONM loss (odds ratio [OR] = 6.68, 95% confidence interval [CI] = 2.45 to 18.23 compared with Types I and II combined). The overall predictive performance with respect to IONM loss (area under the receiver operating characteristic curve = 0.827) was considered excellent.

CONCLUSIONS

This prospective cohort study of patients undergoing spinal deformity correction confirmed that patients with a Type-III spinal cord shape had greater odds of IONM loss. Inclusion of the SCSCS in preoperative risk stratification and intraoperative management of spinal deformity corrective surgery is recommended.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Definition, Frequency and Risk Factors for Intra-Operative Spinal Cord Injury: A Knowledge Synthesis

STUDY DESIGN

Mixed-methods approach.

OBJECTIVES

Intra-operative spinal cord injury (ISCI) is a devastating complication of spinal surgery. Presently, a uniform definition for ISCI does not exist. Consequently, the reported frequency of ISCI and important risk factors vary in the existing literature. To address these gaps in knowledge, a mixed-methods knowledge synthesis was undertaken.

METHODS

A scoping review was conducted to review the definitions used for ISCI and to ascertain the frequency of ISCI. The definition of ISCI underwent formal review, revision and voting by the Guidelines Development Group (GDG). A systematic review of the literature was conducted to determine the risk factors for ISCI. Based on this systematic review and GDG input, a table was created to summarize the factors deemed to increase the risk for ISCI. All reviews were done according to PRISMA standards and were registered on PROSPERO.

RESULTS

The frequency of ISCI ranged from 0 to 61%. Older age, male sex, cardiovascular disease including hypertension, severe myelopathy, blood loss, requirement for osteotomy, coronal deformity angular ratio, and curve magnitude were associated with an increased risk of ISCI. Better pre-operative neurological status and use of intra-operative neuromonitoring (IONM) were associated with a decreased risk of ISCI. The risk factors for ISCI included a rigid thoracic curve with high deformity angular ratio, revision congenital deformity with significant cord compression and myelopathy, extrinsic intradural or extradural lesions with cord compression and myelopathy, intramedullary spinal cord tumor, unstable spine fractures (bilateral facet dislocation and disc herniation), extension distraction injury with ankylosing spondylitis, ossification of posterior longitudinal ligament (OPLL) with severe cord compression, and moderate to severe myelopathy.

CONCLUSIONS

ISCI has been defined as "a new or worsening neurological deficit attributable to spinal cord dysfunction during spine surgery that is diagnosed intra-operatively via neurophysiologic monitoring or by an intraoperative wake-up test, or immediately post-operatively based on clinical assessment". This paper defines clinical and imaging factors which increase the risk for ISCI and that could assist clinicians in decision making.

A Clinical Practice Guideline on the Timing of Surgical Decompression and Hemodynamic Management of Acute Spinal Cord Injury and the Prevention, Diagnosis, and Management of Intraoperative Spinal Cord Injury: Introduction, Rationale, and Scope

STUDY DESIGN

Protocol for the development of clinical practice guidelines following the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) standards.

OBJECTIVES

Acute SCI or intraoperative SCI (ISCI) can have devastating physical and psychological consequences for patients and their families. The treatment of SCI has dramatically evolved over the last century as a result of preclinical and clinical research that has addressed important knowledge gaps, including injury mechanisms, disease pathophysiology, medical management, and the role of surgery. In an acute setting, clinicians are faced with critical decisions on how to optimize neurological recovery in patients with SCI that include the role and timing of surgical decompression and the best strategies for hemodynamic management. The lack of consensus surrounding these treatments has prevented standardization of care across centers and has created uncertainty with respect to how to best manage patients with SCI. ISCI is a feared complication that can occur in the best of hands. Unfortunately, there are no systematic reviews or clinical practice guidelines to assist spine surgeons in the assessment and management of ISCI in adult patients undergoing spinal surgery. Given these limitations, it is the objective of this initiative to develop evidence-based recommendations that will inform the management of both SCI and ISCI. This protocol describes the rationale for developing clinical practice guidelines on (i) the timing of surgical decompression in acute SCI; (ii) the hemodynamic management of acute SCI; and (iii) the prevention, identification, and management of ISCI in patients undergoing surgery for spine-related pathology.

METHODS

Systematic reviews were conducted according to PRISMA standards in order to summarize the current body of evidence and inform the guideline development process. The guideline development process followed the approach proposed by the GRADE working group. Separate multidisciplinary, international groups were created to perform the systematic reviews and formulate the guidelines. All potential conflicts of interest were vetted in advance. The sponsors exerted no influence over the editorial process or the development of the guidelines.

RESULTS

This process resulted in both systematic reviews and clinical practice guidelines/care pathways related to the role and timing of surgery in acute SCI; the optimal hemodynamic management of acute SCI; and the prevention, diagnosis and management of ISCI.

CONCLUSIONS

The ultimate goal of this clinical practice guideline initiative was to develop evidence-based recommendations for important areas of controversy in SCI and ISCI in hopes of improving neurological outcomes, reducing morbidity, and standardizing care across settings. Throughout this process, critical knowledge gaps and future directions were also defined.

The iliac kickstand screw: anatomic CT analysis of screw trajectory and osseous corridor for screw placement

INTRODUCTION

The 'kickstand screw-rod' technique has been recently described for correction of coronal malalignment. This technique utilizes powerful 'construct-to-ilium' distraction between a fixed multi-screw thoracic construct and the ilium, facilitated by a novel 'iliac kickstand screw'. The 'iliac kickstand screw' traverses a previously undescribed osseous corridor in the ilium.

OBJECTIVE

Using a radiographic CT study, the objective is to describe a large osseous corridor within the ilium to accommodate the novel iliac kickstand screw.

METHODS

50 consecutive patients with pelvic CTs at an academic medical center were queried. Simulated iliac kickstand screw trajectories for the left and right hemipelvis were analyzed with 3D visualization software. Maximal screw lengths and dimensions, and trajectories in the osseous corridor were measured.

RESULTS

50 patients' (31 female, 19 male) pelvic CTs were measured with a total of 100 simulated screws. The mean age was 52.4 years and BMI 28.1 ± 7.9. The average length is 119.7 ± 6.6 mm (range 98.7 - 135.3). The narrowest width (maximum potential screw diameter) is 17.8 ± 2.9 mm (coronal) and 20.8 ± 5.3 mm (sagittal). The starting point to the top of the iliac crest is 66.4 mm lateral to midline, and 15.9° caudal in the sagittal and 6.1° lateral in the coronal planes.

CONCLUSIONS

The novel iliac kickstand screw traverses a consistent and large osseous corridor within the ilium. The average simulated screw length is 119.7 mm and maximum potential diameter of 17.8 mm. Starting points relative to the iliac crest are identified.

New Effective Intraoperative Techniques for the Prevention of Coronal Imbalance after Circumferential Minimally Invasive Correction Surgery for Adult Spinal Deformity

This study aimed to devise measures and investigate their effect on coronal imbalance (CI) after circumferential minimally invasive correction surgery (CMIS) with lateral lumbar interbody fusion and percutaneous pedicle screw for adult spinal deformity (ASD). A total of 115 patients with ASD who underwent CMIS from the lower thoracic spine to the ilium were included. Patients were stratified based on the distance between the spinous process of the upper instrumented vertebra and central sacrum vertical line (UIV-CSVL) after the first intraoperative rod application into groups P (UIV-CSVL > 10 mm, n = 50) and G (UIV-CSVL < 10 mm, n = 65). Measures to correct postoperative CI introduced during surgery, preoperative and postoperative UIV-CSVL, and changes in UIV-CSVL after various measures (ΔUIV-CSVL) were investigated in group P. Rod rotation (RR), S2 alar-iliac screw distraction (SD), and kickstand-rod (KR) technique were performed in group P. Group P was further divided into group RR (n = 38), group SD (RR and SD) (n = 7), and group KR (RR and KR) (n = 5); the ΔUIV-CSVLs were 13.9 mm, 20.1 mm, and 24.4 mm in these three groups, respectively. Postoperative C7-CSVL < 10 mm was achieved in all three correction groups. In conclusion, our measures enabled sufficient correction of the UIV-CSVL and are useful for preventing CI after CMIS for ASD.

Comparison of C-Arm-Free Oblique Lumbar Interbody Fusion L5-S1 (OLIF51) with Transforaminal Lumbar Interbody Fusion L5-S1 (TLIF51) for Adult Spinal Deformity

Background and Objectives: Adult spinal deformity (ASD) surgery, L5-S1 lordosis is very important factor. The main objective of the research is to retrospectively compare symptomatic presentation and radiological presentation in the sequelae of oblique lumbar inter-body spinal fusion at L5-S1 (OLIF51) and transforaminal lumbar interbody fusion (TLIF) for ASD. Materials and Methods: We retrospectively evaluated 54 patients who underwent corrective spinal fusion for ASD between October 2019 and January 2021. Thirteen patients underwent OLIF51 (average 74.6 years old, group O) and 41 patients underwent TLIF51 (average 70.5 years old, group T). Mean follow-up period was 23.9 months for group O and 28.9 months for group T, ranging from 12 to 43 months. Clinical and radiographic outcomes are assessed using values including visual analogue scale (VAS) for back pain and Oswestry disability index (ODI). Radiographic evaluation was also collected preoperatively and at 6, 12, and 24 months postoperatively. Results: Surgical time in group O was less than that in group T (356 min vs. 492 min, p = 0.003). However, intraoperative blood loss of both groups were not significantly different (1016 mL vs. 1252 mL, p = 0.274). Changes in VAS and ODI were similar in both groups. L5-S1 angle gain and L5-S1 height gain in group O were significantly better than those of group T (9.4° vs. 1.6°, p = 0.0001, 4.2 mm vs. 0.8 mm, p = 0.0002). Conclusions: Clinical outcomes were not significantly different in both groups, but surgical time in OLIF51 was significantly less than that in TLIF51. The radiographic outcomes showed that OLIF51 created more L5-S1 lordosis and L5-S1 disc height compared with TLIF 51.

Effects of preoperative spinopelvic compensation states on the patient-reported outcomes of adult spinal deformity surgery: three-dimensional motion analysis results

PURPOSE

This study aimed to investigate how preoperative motion analysis results affect the postoperative clinical outcomes of patients undergoing surgery for adult spinal deformity (ASD).

METHODS

Patients who underwent surgery for ASD and whose motion analysis results were available were included. All patients underwent preoperative three-dimensional gait analysis using a motion analysis system. Univariate and multivariate regression analyses were performed to determine the predictive parameters of the 12-month postoperative Oswestry Disability Index (ODI). According to the mean anterior pelvic tilt (Ant-PT) angle in the motion analysis, the patients were divided into two groups: small and high Ant-PT angle groups. The 12-month postoperative ODI between the two groups was compared.

RESULTS

A total of 111 patients who met the inclusion criteria were enrolled in the study. In the multivariate regression analysis, the preoperative sacral slope and mean Ant-PT angle were significant predictors of the 12-month postoperative ODI (p = 0.013 and p = 0.009, respectively). The high Ant-PT angle group showed a poorer 12-month postoperative ODI than did the small Ant-PT angle group, with a mean ODI of 21.9 ± 8.4 and 16.7 ± 8.5, respectively (p = 0.002). Simple linear regression analysis revealed that the Ant-PT angle was positively correlated with the postoperative sagittal vertical axis in all follow-up periods.

CONCLUSION

The study highlights that a high preoperative Ant-PT angle in motion analyses is associated with poor clinical outcomes after surgery for ASD. Therefore, it is necessary to observe and consider the dynamic gait pattern related to the compensatory mechanism for sagittal imbalance in the decision-making process for ASD surgery.

Transcranial Motor-evoked Potentials for Intraoperative Nerve Root Monitoring During Adult Spinal Deformity Surgery: A Prospective Multicenter Study

STUDY DESIGN

A prospective, multicenter study.

OBJECTIVE

This study clarified the uses and limitations of transcranial motor-evoked potentials (Tc-MEPs) for nerve root monitoring during adult spinal deformity (ASD) surgeries.

SUMMARY OF BACKGROUND DATA

Whether Tc-MEPs can detect nerve root injuries (NRIs) in ASD surgeries remains controversial.

MATERIALS AND METHODS

We prospectively analyzed neuromonitoring data from 14 institutions between 2017 and 2020. The subjects were ASD patients surgically treated with posterior corrective fusion using multichannel Tc-MEPs. An alert was defined as a decrease of ≥70% in the Tc-MEP's waveform amplitude from baseline, and NRI was considered as meeting the focal Tc-MEP alerts shortly following surgical procedures with postoperative nerve root symptoms in the selected muscles.

RESULTS

A total of 311 patients with ASD (262 women and 49 men) and a mean age of 65.5 years were analyzed. Tc-MEP results revealed 47 cases (15.1%) of alerts, including 25 alerts after 10 deformity corrections, six three-column osteotomies, four interbody fusions, three pedicle screw placements or two decompressions, and 22 alerts regardless of surgical maneuvers. Postoperatively, 14 patients (4.5%) had neurological deterioration considered to be all NRI, 11 true positives, and three false negatives (FN). Two FN did not reach a 70% loss of baseline (46% and 65% loss of baseline) and one was not monitored at target muscles. Multivariate logistic regression analysis revealed that risk factors of NRI were preexisting motor weakness ( P <0.001, odds ratio=10.41) and three-column osteotomies ( P =0.008, odds ratio=7.397).

CONCLUSIONS

Nerve root injuries in our ASD cohort were partially predictable using multichannel Tc-MEPs with a 70% decrease in amplitude as an alarm threshold. We propose that future research should evaluate the efficacy of an idealized warning threshold (e.g., 50%) and a more detailed evoked muscle selection, in reducing false negatives.

Predictive factors for successful non-operative treatment and achieving MCID improvement in health-related quality of life in adult spinal deformity

Background

Adult spinal deformity is a spectrum of degenerative spinal diseases with increasing prevalence and healthcare burden worldwide. Identification of patients who are more likely to improve through conservative management may reduce cost and potentially prevent surgery and its associated costs and complications. This study aims to identify predictive factors for MCID in improvement of ODI and SRS-22r questionnaires in patients with adult spinal deformity treated with conservative treatment.

Methods

A prospective, observational cohort study of 46 patients was conducted at a spine specialist clinic. Inclusion criteria were 30–80 years of age, diagnosis of neglected adolescent idiopathic scoliosis, de-novo scoliosis, degenerative spondylolisthesis, and sagittal plane deformities (thoracic hypokyphosis, lumbar hypolordosis), presenting with mechanical back pain with or without radicular leg pain. All patients received conservative management including medication and physiotherapy. Radiological and clinical parameters were measured at baseline and at 1-year follow-up. Primary outcomes were ODI and SRS-22r scores. Secondary outcomes were EQ-5D-5L scores and requiring spine surgery during conservative treatment. Predictors for MCID improvement in ODI and SRS-22r were identified using multivariate regressions and receiver operating characteristic (ROC) analyses.

Results

At baseline, patients who reached MCID in ODI and/or SRS-22r showed less comorbidities (diabetes mellitus, hypertension, ischemic heart disease, osteoarthritis, cancer), smaller range of lateral spinal flexion, larger trunk shift, larger pelvic incidence, a higher EQ-5D-5L anxiety/depression dimension score, a lower SRS-22r total score, and presence of spondylolisthesis. Lateral flexion range < 25 degrees, trunk shift > 14 mm, pelvic incidence > 50 degrees, EQ-5D-5L anxiety/depression dimension score > 1, and SRS-22r total score < 3.5 were the cut-off values generated by ROC analysis.

Conclusions

Both radiological and clinical predictive factors for MCID improvement in health-related quality of life were identified. Future research should identify subgroups of patients who are responsive to specific conservative treatment modalities, so as to provide information for personalized medicine.

Level of evidence

II

Comprehensive Perioperative Approach to Complex Spine Deformity Management

OBJECTIVE

Study perioperative strategies for optimizing neuroprotection in complex spine deformity correction surgery.

METHODS

We report the case of a patient with severe lumbar dextroscoliosis, thoracolumbar junction hyperkyphosis with a 40-degree Cobb angle levoconvex scoliosis who underwent spinal deformity correction with loss of neuromonitoring during surgery. We performed a literature review on perioperative management of complex spine deformity.

RESULTS

A 50-year-old man presented with lumbar pain and right L4 radiculopathy. Surgical intervention for deformity correction and decompression was indicated with T4-L4 posterior instrumentation L2/L3 and L3/L4 transforaminal lumbar interbody fusion. Surgery was aborted due to the loss of neuromonitoring. Postsurgery, the patient had left sensory deficit and the neurocritical care team clinically suspected and deduced the anatomic location of the spinal cord compression. Magnetic resonance imaging confirmed a T10-T11 hyperintensity suggestive of cord ischemia due to osteophyte compressing the spinal cord. The patient underwent a second corrective surgery with no intraoperative events and has no long-term neurological sequela.

CONCLUSIONS

This case illustrates that a comprehensive perioperative approach and individualized risk factor assessment is useful in complex spine deformity surgery. Further research is needed to determine how this individualized comprehensive approach can lead to intraoperative and postoperative countermeasures that improved spine surgery outcomes.

LEVEL OF EVIDENCE

Level V.

Establishing consensus: determinants of high-risk and preventative strategies for neurological events in complex spinal deformity surgery

PURPOSE

To establish expert consensus on various parameters that constitute elevated risk during spinal deformity surgery and potential preventative strategies that may minimize the risk of intraoperative neuromonitoring (IONM) events and postoperative neurological deficits.

METHODS

Through a series of surveys and a final virtual consensus meeting, the Delphi method was utilized to establish consensus among a group of expert spinal deformity surgeons. During iterative rounds of voting, participants were asked to express their agreement (strongly agree, agree, disagree, strongly disagree) to include items in a final set of guidelines. Consensus was defined as ≥ 80% agreement among participants. Near-consensus was ≥ 60% but < 80% agreement, equipoise was ≥ 20% but < 60%, and consensus to exclude was < 20%.

RESULTS

Fifteen of the 15 (100%) invited expert spinal deformity surgeons agreed to participate. There was consensus to include 22 determinants of high-risk (8 patient factors, 8 curve and spinal cord factors, and 6 surgical factors) and 21 preventative strategies (4 preoperative, 14 intraoperative, and 3 postoperative) in the final set of best practice guidelines.

CONCLUSION

A resource highlighting several salient clinical factors found in high-risk spinal deformity patients as well as strategies to prevent neurological events was successfully created through expert consensus. This is intended to serve as a reference for surgeons and other clinicians involved in the care of spinal deformity patients.

LEVEL OF EVIDENCE

Level V.

Kickstand Rod With Asymmetric Pedicle Subtraction Osteotomy for Treatment of Adult Kyphoscoliosis With Severe Coronal Imbalance

BACKGROUND

The kickstand rod has been described for the treatment of severe coronal imbalance. We present a modified description that combines an asymmetric pedicle subtraction osteotomy (PSO) for correction of severe kyphoscoliosis.

OBJECTIVE

To describe the use of a temporary kickstand rod.

METHODS

Type 1 osteotomies were performed across the main and fractional curves. An asymmetric PSO was performed at the apex of the main curve, and a kickstand rod placed on the concavity anchored from the ilium to a temporary connector above the main curve. Distraction was applied across the kickstand rod because the PSO was closed on the convexity. A permanent rod was placed contralateral to the kickstand, followed by replacement of the kickstand with a permanent rod and bilateral accessory rods.

RESULTS

A 66-year-old man presented with kyphoscoliosis causing severe coronal and sagittal imbalance. He underwent L4-S1 anterior lumbar interbody fusion followed by T4-pelvis instrumented fusion the following day. Type 1 osteotomies were performed from T6-T12 to L3-S1 and an asymmetric PSO at L2. A temporary kickstand rod was used to distract across the concavity because the PSO was closed on the convexity. The patient achieved excellent clinical and radiographical results.

CONCLUSION

When used in conjunction with appropriate osteotomies, the kickstand rod can aid in correction of severe coronal imbalance. Use of a temporary kickstand rod is technically easier and allows for correction of the main and fractional curves when used with an asymmetric PSO.

Conditions for Achieving Postoperative Pelvic Incidence-Lumbar Lordosis < 10° in Circumferential Minimally Invasive Surgery for Adult Spinal Deformity

This retrospective study aimed to evaluate the clinical outcomes of circumferential minimally invasive surgery (CMIS) using lateral lumbar interbody fusion (LLIF) and percutaneous pedicle screw (PPS) in adult spinal deformity (ASD) patients, and to clarify the conditions for achieving postoperative pelvic incidence-lumbar lordosis (PI-LL) < 10°. Demographics and other parameters of ASD patients who underwent CMIS and who were divided into groups G (achieved postoperative PI-LL < 10°) and P (PI-LL ≥ 10°) were compared. Of the 145 included ASD patients who underwent CMIS, the average fused level, bleeding volume, operative time, and number of intervertebral discs that underwent LLIF were 10.3 ± 0.5 segments, 723 ± 375 mL, 366 ± 70 min, and 4.0 segments, respectively. The rod material was titanium alloy in all the cases. The PI-LL significantly improved from 37.3 ± 17.9° to 1.2 ± 12.2° postoperatively. Pre- and postoperative PI, postoperative LL, preoperative PI-LL, PI-LL after LLIF, and postoperative PI-LL were significantly larger in group P. PI-LL after LLIF was identified as a significant risk factor of postoperative PI-LL < 10° by logistic regression, and the cut-off value on receiver operating characteristic curve analysis was 20°. Sufficient correction was achieved by CMIS. If PI-LL after LLIF was ≤20°, it was corrected to the ideal alignment by the PPS procedure.

Two- and three-year outcomes of minimally invasive and hybrid correction of adult spinal deformity

OBJECTIVE

Previous studies have demonstrated the short-term radiographic and clinical benefits of circumferential minimally invasive surgery (cMIS) and hybrid (i.e., minimally invasive anterior or lateral interbody fusion with an open posterior approach) techniques to correct adult spinal deformity (ASD). However, it is not known if these benefits are maintained over longer periods of time. This study evaluated the 2- and 3-year outcomes of cMIS and hybrid correction of ASD.

METHODS

A multicenter database was retrospectively reviewed for patients undergoing cMIS or hybrid surgery for ASD. Patients were ≥ 18 years of age and had one of the following: maximum coronal Cobb angle (CC) ≥ 20°, sagittal vertical axis (SVA) > 5 cm, pelvic incidence-lumbar lordosis mismatch (PI-LL) ≥ 10°, or pelvic tilt (PT) > 20°. Radiographic parameters were evaluated at the latest follow-up. Clinical outcomes were compared at 2- and 3-year time points and adjusted for age, preoperative CC, levels operated, levels with interbody fusion, presence of L5-S1 anterior lumbar interbody fusion, and upper and lower instrumented vertebral level.

RESULTS

Overall, 197 (108 cMIS, 89 hybrid) patients were included with 187 (99 cMIS, 88 hybrid) and 111 (60 cMIS, 51 hybrid) patients evaluated at 2 and 3 years, respectively. The mean (± SD) follow-up duration for cMIS (39.0 ± 13.3 months, range 22-74 months) and hybrid correction (39.9 ± 16.8 months, range 22-94 months) were similar for both cohorts. Hybrid procedures corrected the CC greater than the cMIS technique (adjusted p = 0.022). There were no significant differences in postoperative SVA, PI-LL, PT, and sacral slope (SS). At 2 years, cMIS had lower Oswestry Disability Index (ODI) scores (adjusted p < 0.001), greater ODI change as a percentage of baseline (adjusted p = 0.006), less visual analog scale (VAS) back pain (adjusted p = 0.006), and greater VAS back pain change as a percentage of baseline (adjusted p = 0.001) compared to hybrid techniques. These differences were no longer significant at 3 years. At 3 years, but not 2 years, VAS leg pain was lower for cMIS compared to hybrid techniques (adjusted p = 0.032). Those undergoing cMIS had fewer overall complications compared to hybrid techniques (adjusted p = 0.006), but a higher odds of pseudarthrosis (adjusted p = 0.039).

CONCLUSIONS

In this review of a multicenter database for patients undergoing cMIS and hybrid surgery for ASD, hybrid procedures were associated with a greater CC improvement compared to cMIS techniques. cMIS was associated with superior ODI and back pain at 2 years, but this difference was no longer evident at 3 years. However, cMIS was associated with superior leg pain at 3 years. There were fewer complications following cMIS, with the exception of pseudarthrosis.

Femoral head to lower lumbar neural foramen distance as a novel radiographic parameter to predict postoperative stretch neuropraxia

OBJECTIVE

Lumbosacral fractional curves in adult spinal deformity (ASD) patients often have sharp coronal curves resulting in significant pain and imbalance. Postoperative stretch neuropraxia after fractional curve correction can lead to discomfort and unsatisfactory outcomes. The goal of this study was to use radiographic measures to increase understanding of the relationship between postoperative stretch neuropraxia and fractional curve correction.

METHODS

In 62 ASD patients treated from 2015 to 2018, radiographic review was performed, including measurement of the distance between the lower lumbar neural foramen (L4 and L5) in the concavity and convexity of the lumbosacral fractional curve and the ipsilateral femoral heads (FHs; L4-FH and L5-FH) in pre- and postoperative anteroposterior spine radiographs. The largest absolute preoperative to postoperative change in distance between the lower lumbar neural foramen and the ipsilateral FH (ΔL4/L5-FH) was used for analysis. Chi-square analyses, independent and paired t-tests, and logistic regression were performed to study the relationship between L4/L5-FH and stretch neuropraxia for categorical and continuous variables, respectively.

RESULTS

Of the 62 patients, 13 (21.0%) had postoperative stretch neuropraxia. Patients without postoperative stretch neuropraxia had an average ΔL4-FH distance of 16.2 mm compared to patients with stretch neuropraxia, who had an average ΔL4-FH distance of 31.5 mm (p < 0.01). Patients without postoperative neuropraxia had an average ΔL5-FH distance of 11.1 mm compared to those with stretch neuropraxia, who had an average ΔL5-FH distance of 23.0 mm (p < 0.01). Chi-square analysis showed that patients had a 4.78-fold risk of developing stretch neuropraxia with ΔL4-FH > 20 mm (95% CI 1.3-17.3) and a 5.17-fold risk of developing stretch neuropraxia with ΔL5-FH > 15 mm (95% CI 1.4-18.7). Logistic regression analysis indicated that the odds of developing stretch neuropraxia were 15:1 with a ΔL4-FH > 20 mm (95% CI 3-78) and 21:1 with a ΔL5-FH > 15 mm (95% CI 4-113).

CONCLUSIONS

The novel ΔL4/L5-FH distances are strongly associated with postoperative stretch neuropraxia in ASD patients. A ΔL4-FH > 20 mm and ΔL5-FH > 15 mm significantly increase the odds for patients to develop postoperative stretch neuropraxia.

Do Adult Spinal Deformity Patients Undergoing Surgery Continue to Improve From 1-Year to 2-Years Postoperative?

OBJECTIVE

Evaluate clinical improvement as measured by patient-reported outcomes (PROs) during the 1 to 2-year interval.

STUDY DESIGN

Retrospective Cohort.

METHODS

A single-institution registry of ASD patients undergoing surgery was queried for patients with ≥6 level fusions. Demographics and radiographic variables were collected. PROs collected were the ODI and SRS-22r scores at: preoperative, 1-year and 2-years. Outcome measures of clinical improvement during the 1-2 year time interval were: 1) group medians, 2) percent minimum clinically important difference (MCID), and 3) percent minimal symptom scale (MSS)(ODI < 20 or SRS-pain + function >8). Wilcoxon rank-sum tests, chi-squared tests, Kruskal-Wallis tests, and logistic regression were performed.

RESULTS

157 patients undergoing ASD surgery with minimum of 1-year follow-up were included. Mean age was 53.2 and mean instrumented levels was 13.1. Preoperative alignment was: Neutral Alignment (NA) 49%, Coronal Malalignment (CM) 17%, Sagittal Malalignment (SM 17%), and Combined Coronal/Sagittal Malalignment (CCSM) 18%. Preoperative to 1-year, and preoperative to 2-years, all ODI/SRS-22r significantly improved (P < .001). In all patients, the only significant improvement in PROs between 1-and 2-year postoperative were those reaching ODI MCID (69% 1-year vs. 84% 2-years; P < .001). Subgroup analysis: ≥55 years had an improved median ODI (18 vs. 8; P = .047) and an improved percent achieving ODI MCID (73% vs. 84%, P = .048). CCSM patients experienced significant improvement in SRS-appearance score (75% vs. 100%; P = .050), along with those with severe preoperative SM >7.5 cm (73% vs. 100%; P = .032).

CONCLUSIONS

Most ASD patients experience the majority of PRO improvement by 1-year postoperative. However, subsets of patients that may continue to improve up to 2-years postoperative include patients ≥55 years, combined coronal/sagittal malalignment, and those with severe sagittal malalignment ≥7.5 cm.

Correction of a severe coronal malalignment in adult spinal deformity using the "kickstand rod" technique as primary surgery

Objective

Adult spinal deformity (ASD) is a growing healthcare issue due to the aging population. A satisfying spine balance in both sagittal and coronal planes is achieved through surgery. Only few studies about the coronal alignment correction with the kickstand rod were reported in the literature, until now. The aim of the present study was to describe clinical and radiological outcomes of the Kickstand rod (KR) technique in a series of ASD patients with severe coronal malalignment after 1 year of follow-up.

Material and methods

Six patients affected by ASD with severe CM who underwent surgery between 2018 and 2019 were retrospectively analyzed. The mean follow up was 14 months. All patients had posterior-only approach with long pelvic-thoracic fixation according to the Kickstand rod technique.

Results

Postoperative alignment and pain numerical rating scale scores significantly improved. No instrumentation complications occurred. A coronal alignment improvement from a mean of 163 mm preoperatively to a mean of 32 mm postoperatively was observed.

Conclusion

KR technique appears to be a safe and efficient way for coronal and sagittal imbalance correction in ASD patients. Although technically demanding, by using this technique good and stable radiological and functional outcomes are achieved especially in selected patients.

Risk factors of unintended return to the operating room in adult spinal deformity

Background

To evaluate the incidence and risk factors associated with unintended return to the operating room in adult spinal deformity after spinal deformity corrective surgery.

Methods

Retrospect of 141 adult spinal deformity patients in a single institution between January 2017 and December 2019. Inclusion criteria enrolled 18 to 80 years old patients who diagnosed with congenital/idiopathic/syndromic/acquired spinal deformity underwent posterior corrective spinal surgery. The surgical details and complications were recorded. The rate of unintended return to the operating room (UIROR) during hospitalization was examined, and the risk factors of unintended return to the operating room were investigated via multivariate analysis.

Results

This is a retrospective study. One hundred and forty-one patients who underwent spinal deformity surgery with a mean age of 31.8 years (range 18-69 years) were studied. The rate of unintended return to the operating room was 10.64% (15/141). Two of 15 patients had twice unintended surgery during hospitalization (13.33%). The most principal complication was neurologic deficit (73.3%); six of 15 postoperative present implants deviation causes severe lower limbs radiating pain (40%). The multivariate analysis shows higher apical vertebral rotation (AVR>grade II, odds ratio [OR] = 9.362; 95% CI= 1.930-45.420; P= .006), obesity (OR = 11.448; 95% CI= 1.320-99.263; P= .027), and previous neurological symptom (OR = 7.358; 95% CI= 1.798-30.108; P= .006) were independent predictors of unintended return to the operating room.

Conclusion

Postoperative neurologic deficit and short-term implant malposition are essential causes of unintended return to the operating room in adult spinal deformity patients. Preoperative factors such as higher AVR (> grade II), obesity, and previous neurological symptom may significantly increase the risk of morbidity in UIROR. Spine surgeons should be alert to these risk factors and require adequate preoperative evaluations to reduce the incidence of unintended return to the operating room.

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.

Development and Validation of a Multidomain Surgical Complication Classification System for Adult Spinal Deformity

STUDY DESIGN

Prospective analysis of example cases.

OBJECTIVE

The aim of this study was to analyze the accuracy and repeatability of a new comprehensive classification system for capturing complications data in adult spinal deformity.

SUMMARY OF BACKGROUND DATA

Complications are common in adult spinal deformity surgery. However, no consensus exists on the definition or classification of complications in adult spinal deformity surgery. The lack of consensus significantly limits understanding of complications' effects on outcomes in surgery for adult spinal deformity.

METHODS

Using a Delphi method, members of the International Spine Study Group, AO Spine, and the European Spine Study Group collaborated to develop an adult spinal deformity classification system. The multidomain classification system accounts for medical complications (cancer, cardiopulmonary, central nervous system, gastrointestinal, infectious, musculoskeletal, renal) and surgical complications (implant complications, radiographic complications, neurologic events, intraoperative events, and wound complications). Seventeen individuals ("event readers"), including spine surgeons, trainees, and research coordinators, used the new classification system two separate times to analyze complications in ten example cases. The accuracy and repeatability of the classification system were subsequently calculated based on the providers' responses for the example cases.

RESULTS

The 10 example cases included 22 complications. Nearly 95% of complications were captured by >95% of the event readers. The system demonstrated good repeatability of 86.9% between the first and second set of responses provided by event readers.

CONCLUSION

The ISSG-AO Multi-Domain Spinal Deformity Complication Classification System for Adult Spinal Deformity demonstrated good accuracy and repeatability among both surgeons and research coordinators in capturing complications in adult spinal deformity surgery. The ISSG-AO system may be applied to help better understand the impact of complications on outcomes and costs in adult spinal deformity surgery.Level of Evidence: 5.

The Scoliosis Research Society adult spinal deformity standard outcome set

PURPOSE

Symptomatic adult spinal deformity (ASD) with an extremely variable presentation with pain, with and without neurogenic leg pain, and/or disturbed sagittal and coronal balance, causes a significant societal burden of disease. It is an important consequence of the aging adult population, generating a plethora of spine-related interventions with variable treatment efficacy and consistently high costs. Recent years have witnessed more than a threefold increase in the prevalence and treatment of ASD, and further increases over the coming decades are expected with the growing elderly population worldwide. The ability to monitor and assess clinical outcomes has not kept pace with these developments. This paper addresses the pressing need to provide a set of common outcome metrics for this growing group of patients with back pain and other disabilities due to an adult spinal deformity.

METHODS

The standard outcome set was created by a panel with global representation, using a thorough modified Delphi procedure. The three-tiered outcome hierarchy (Porter) was used as a framework to capture full cycle of care. The standardized language of the International Classification of Functioning, Disability and Health (WHO-ICF) was used.

RESULTS

Consensus was reached on a core set of 25 WHO-ICF outcome domains ('What to measure'); on the accompanying globally available clinician and patient reported measurement instruments and definitions ('How to measure'), and on the timing of the measurements ('When to measure'). The current work has brought to light domains not routinely reported in the spinal literature (such as pulmonary function, return to work, social participation), and domains for which no adequate instruments have yet been identified (such as how to clinically quantify in routine practice lumbar spinal stenosis, neurogenic claudication, radicular pain, and loss of lower extremity motor function).

CONCLUSION

A standard outcome set was developed for patients undergoing treatment for adult spinal deformity using globally available outcome metrics. The current framework can be considered a reference for further work, and may provide a starting point for routine methodical and systematic monitoring of outcomes. Post-COVID e-health may accelerate the routine capture of these types of data.

A Radiographic Analysis of Lumbar Fusion Status and Instrumentation Failure After Complex Adult Spinal Deformity Surgery With Spinopelvic Fixation: Two-Year Follow-up From the Scoli-Risk-1 Prospective Database

STUDY DESIGN

A retrospective review of prospectively collected data.

OBJECTIVE

The objective of this study was to investigate the fusion status of the lumbar spine and lumbosacral junction at 2 years postoperatively after complex adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Achieving fusion is crucial for maintaining optimal alignment in ASD surgery. However, prospective data assessing fusion status using large patient populations are lacking in this patient population.

MATERIALS AND METHODS

Postoperative radiographs of 162 patients from the Scoli-Risk-1 database, who underwent complex ASD surgery with fusion to the sacrum, were evaluated by 3 independent spine surgeons at 6-week, 6-month, and 2-year follow-up. The fusion rate of the lumbar spine segments at a 2-year follow-up was determined by using previously published radiographic grading criteria. We also assessed the prevalence of instrumentation failures.

RESULTS

The interrater reliabilities for grading the fusion status were overall fair at each level evaluated (Fleiss κ, 0.337-0.439). Overall, 70.3% (114/162) demonstrated the solid fusion of the entire lumbar spine at a 2-year follow-up. The fusion rates of each segment were L1/L2: 87.0%, L2/L3: 82.0%, L3/L4: 83.9%, L4/L5: 89.5%, and L5/S1: 89.5%. Pedicle screw loosening was the most frequent implant failure throughout the observation period (9.2%, 11.6%, and 11.0% at 6-wk, 6-mo, and 2-y follow-up, respectively). No rod breakage was observed at 6 weeks, increasing to 9.8% at 2-year follow-up. The prevalence of postoperative proximal junctional kyphosis was 5.5% at 6 weeks, showing no difference at 2 years postoperative.

CONCLUSIONS

In this series of complex ASD surgeries often requiring 3-column osteotomies, 70.3% showed solid fusion of the entire lumbar spine, including the lumbosacral junction. The lumbosacral segments showed a relatively high fusion rate at a 2-year follow-up likely due to the frequent use of anterior column support and graft. The prevalence of rod breakage increased as follow-up proceeded to 9.8%, which was most commonly observed at the lumbosacral junction.

LEVEL OF EVIDENCE

Level IV.

State of the art review: Vertebral Osteotomies for the management of Spinal Deformity

Spinal deformity is a complex condition caused by various etiologies (degenerative, neuromuscular, congenital, developmental, traumatic, neoplastic, idiopathic) leading to clinical deformity, axial back pain, and neurologic deficits. Patients presenting with severe deformities require vertebral osteotomies to achieve the necessary curve correction for radiographic and clinical improvement. The three major vertebral osteotomy techniques commonly used at this time are the posterior column osteotomy (PCO), pedicle subtraction osteotomy (PSO), and vertebral column resection (VCR). The different vertebral osteotomies have unique merits and pitfalls that need to be addressed during preoperative planning to achieve maximum benefit while limiting or avoiding possible complications. The more difficult vertebral osteotomies have a steeper learning curve and requires extensive pre, intra and postoperative management of the patient. This review will aim to discuss the indications, surgical techniques, and clinical outcomes for each of these different vertebral osteotomy techniques with illustrative cases.

Complications of thoracic spine surgery - Their avoidance and management

As the surgical techniques have been significantly developed, thoracic spine surgery is currently increasingly indicated for a variety of pathologies such as degenerative spondylosis, ligament ossification, spinal deformity, infectious diseases, trauma and tumors. Thoracic spine has the distinctive anatomy with the rib attachment and the proximity to great vessels and lungs, and spinal cord has particular vulnerability due to its unique circulation system. Thus, both anterior and posterior approach surgeries have their own risks unique to this spinal segment. To be capable of challenging the spinal disorders in thoracic spine, surgeons must be aware of possible complications and their avoidance methods as well as management strategy. In the present narrative review paper, the complications in thoracic spine surgery are categorized into approach-related complications, neurological complications, wound-related complications, mechanical and instrument-related complications, as well as medical complications along with pre-, intra- and post-operative considerations. Their pathologies, possible sequelae, incidence, risk factors, prevention and management are discussed. As for some of the complications that are also commonly seen in cervical or lumbar spine, focus is placed on their importance in thoracic spine surgery. To prevent these adverse events associated with thoracic spine surgery, surgeons should be familiar with detailed knowledge of thoracic anatomy related to its approach as well as physiological characteristics.

Anterior Column Realignment: Analysis of Neurological Risk and Radiographic Outcomes

BACKGROUND

Anterior column realignment (ACR) is a less invasive alternative to 3-column osteotomy for the correction of sagittal imbalance. We hypothesized that ACR would correct sagittal imbalance with an acceptable neurological risk.

OBJECTIVE

To assess long-term neurological and radiographic outcomes after ACR.

METHODS

Patients ≥18 yr who underwent ACR from 2005 to 2013 were eligible. Standing scoliosis radiographs were studied at preoperation, postoperation (≤6 wk), and at minimum 2 yr of follow-up. Clinical/radiographic data were collected through a retrospective chart review, with thoracic 1 spino-pelvic inclination (T1SPi) used as the angular surrogate for sagittal vertical axis.

RESULTS

A total of 26 patients had complete data, with a mean follow-up of 2.8 yr (1.8-7.4). Preoperative, sagittal parameters were lumbar lordosis (LL) of -16.1°, pelvic incidence (PI)-LL of 41.7°, T1SPi of 3.6°, and pelvis tilt (PT) of 32.4°. LL improved by 30.6° (P < .001) postoperation. Mean changes in PT (-8.3), sacral slope (8.9), T1SPi (-4.9), and PI-LL (-33.5) were all significant. The motion segment angle improved by 26.6°, from 5.2° to -21.4° (P < .001). Neurological complications occurred in 32% patients postoperation (n = 8; 1 patient with both sensory and motor). New thigh numbness/paresthesia developed in 3 (13%) patients postoperation; only 1 (4%) persisted at latest follow-up. A total of 6 (24%) patients developed a new lower extremity motor deficit postoperation, with 4 (8%) having persistent new weakness at last follow-up. Out of 8 patients with preoperative motor deficit, half saw improvement postoperation and 75% improved by last follow-up.

CONCLUSION

There was net motor improvement, with 24% of patients improving and 16% having persistent new weakness at latest follow-up; 60% were unchanged. Radiographic results demonstrate that ACR is a useful tool to treat severe sagittal plane deformity.

The Treatment of Perioperative Spinal Cord Injury With Hyperbaric Oxygen Therapy: A Case Report

STUDY DESIGN

Case report (level IV evidence).

OBJECTIVE

To describe a potential novel application of hyperbaric oxygen therapy (HBOT) in the successful treatment of a postoperative spinal cord injury.

SUMMARY OF BACKGROUND DATA

A 68-year-old man presented with an acute spinal cord injury (ASIA impairment scale D), on the background of degenerative lower thoracic and lumbar canal stenosis. He underwent emergent decompression and instrumented fusion (T9-L5), with an uncomplicated intraoperative course and no electrophysiological changes. Immediate postoperative assessment demonstrated profound bilateral limb weakness (1/5 on the Medical Research Council [MRC] grading scale, ASIA impairment scale B), without radiological abnormality.

METHODS

Conventional medical management (hypertension, level 2 care) was instigated with the addition of Riluzole, with no effect after 30 hours. At 36 hours 100% oxygen at 2.8 atmospheres was applied for 90 minutes, and repeated after 8 hours, with a further three treatments over 48 hours.

RESULTS

The patient demonstrated near-immediate improvement in lower limb function to anti-gravity (MRC grading 3/5) after one treatment. Motor improvement continued over the following treatments, and after 2 weeks the patient was ambulatory. At 4 months, the patient demonstrated normal motor function with no sphincteric disturbance.

CONCLUSION

The application of HBOT contributed to the immediate and sustained improvement (ASIA B to ASIA E) in motor recovery after postoperative spinal cord injury. HBOT may represent a new avenue of therapy for spinal cord injury, and requires further prospective investigation.

LEVEL OF EVIDENCE

4.

A novel MRI-based classification of spinal cord shape and CSF presence at the curve apex to assess risk of intraoperative neuromonitoring data loss with thoracic spinal deformity correction

STUDY DESIGN

Retrospective cohort. We present a simple classification system that is able to identify patients with increased odds of losing intraoperative neuromonitoring data during thoracic deformity correction. Type 3 spinal cords, with the cord deformed against the concave pedicle in the axial plane, have ×28 greater odds of losing monitoring data during surgery.

OBJECTIVES

Assess preoperative morphology of the spinal cord across the thoracic concavity to predict intraoperative loss of neuromonitoring data.

METHODS

128 consecutive patients undergoing surgical correction of a thoracic deformity with pedicle screw/rod constructs were included. Spinal cords were classified into 3 types based on the appearance of the cord on the axial-T2 MRI at the apex of the curve. Type 1 is defined as a circular/symmetric cord with visible CSF between the cord and the apical concave pedicle/vertebral body. Type 2 is a circular/oval/symmetric cord with no visible CSF between the concave pedicle and the cord. Type 3 is a spinal cord that is flattened/deformed by the apical concave pedicle or vertebral body, with no intervening CSF (Fig. 1).

RESULTS

128 patients were reviewed: 81 (63%) Type 1; 32 (25%) Type 2; and 12 (11.7%) Type 3 spinal cords. Lower extremity trans-cranial motor-evoked Potentials (MEPs) and/or somatosensory evoked potentials (SSEPs) were lost intraoperatively in 21 (16%) cases, with full recovery of data in 20 of those cases. On regression analysis, a Type 1 cord was protective against intraoperative data loss (OR = 0.17, p = 0.0003). Type 2 cords had no association with data loss (OR = 0.66, p = 0.49). Type 3 cords had significantly higher odds of intraoperative data loss (OR = 28.3, p < 0.0001).

CONCLUSIONS

We present a new spinal cord risk classification scheme to identify patients with increased odds of losing spinal cord monitoring data with thoracic deformity correction. The odds of losing intraoperative MEPs/SSEPs are greater in type 3 spinal cords.

LEVEL OF EVIDENCE

III.

The Natural History of Progression in Adult Spinal Deformity: A Radiographic Analysis

STUDY DESIGN

Historical cohort study.

OBJECTIVE

To evaluate progression in the coronal and sagittal planes in nonsurgical patients with adult spinal deformity (ASD).

METHODS

A retrospective analysis of nonsurgical ASD patients between 2005 and 2017 was performed. Magnitude of the coronal and sagittal planes were compared on the day of presentation and at most recent follow-up. Previous reported prognostic factors for progression in the coronal plane, including the direction of scoliosis, curve magnitude, and the position of the intercrest line (passing through L4 or L5 vertebra), were studied.

RESULTS

Fifty-eight patients were included with a mean follow-up of 59.8 ± 34.5 months. Progression in the coronal plane was seen in 72% of patients. Mean Cobb angle on the day of presentation and most recent follow-up was 37.2 ± 14.6° and 40.8° ± 16.5°, respectively. No significant differences were found in curve progression in left- versus right-sided scoliosis (3.3 ± 7.1 vs 3.7 ± 5.4, P = .81), Cobb angle <30° versus ≥30° (2.6 ± 5.0 vs 4.3 ± 6.5, P = .30), or when the intercrest line passed through L4 rather than L5 vertebra (3.4 ± 5.0° vs 3.8 ± 7.1°, P = .79). No significant differences were found in the sagittal plane between presentation and most recent follow-up.

CONCLUSIONS

This is the first study that describes progression in the coronal and sagittal planes in nonsurgical patients with ASD. Previous reported prognostic factors were not confirmed as truly relevant. Although progression appears to occur, large variation exists and these results may not be directly applicable to the individual patient.

The "kickstand rod" technique for correction of coronal imbalance in patients with adult spinal deformity: initial case series

OBJECTIVE

The objective of this study was to describe and evaluate a new surgical procedure for the correction of coronal imbalance (CI) in adult spinal deformity patients, called the "kickstand rod" technique.

METHODS

The authors analyzed the records of 24 consecutive patients with pediatric and adult spinal deformity and CI treated between July 2015 and October 2017 with a long-segment fusion and a kickstand rod. For the kickstand rod technique, an iliac screw was placed on the ipsilateral side of the trunk shift and connected proximally through a side-by-side domino link to the thoracolumbar junction; this rod was distracted to promote coronal plane balancing. Distraction occurred with the rod on the contralateral side locked in order to preserve sagittal correction. Radiographic and clinical analyses were conducted to evaluate the outcomes and possible complications of the kickstand rod technique.

RESULTS

The mean age of the patients was 55 years (range 14-73 years). Eighteen of the 24 patients were female. CI preoperatively was a mean of 63 mm, and the mean measurement at the final follow-up (mean duration 1.4 years) was 47 mm. There were no neurological, vascular, or implant-related complications in any of the patients. One patient developed wound dehiscence that was successfully treated without implant removal, and one developed proximal junctional kyphosis requiring extension of the construct proximally. One patient also returned to the operating room for excision of a spinous process. There were no complaints about screw prominence, kickstand construct failure, or significant worsening of CI after surgery.

CONCLUSIONS

The kickstand rod technique is safe and effective for the correction of CI in spinal deformity patients. This technique was found to provide marked coronal correction and additional strength to the overall construct without significant adverse consequences.

Minimally Invasive Spinal Deformity Surgery: Analysis of Patients Who Fail to Reach Minimal Clinically Important Difference

BACKGROUND

It is well known that clinical improvements following surgical intervention are variable. While all surgeons strive to maximize reliability and degree of improvement, certain patients will fail to achieve meaningful gains. We aim to analyze patients who failed to reach minimal clinically important difference (MCID) in an effort to improve outcomes for minimally invasive deformity surgery.

METHODS

Data were collected on a multicenter registry of minimally invasive surgery adult spinal deformity surgeries. Patient inclusion criteria were age ≥18 years, coronal Cobb ≥20 degrees, pelvic incidence-lumbar lordosis ≥10 degrees, or a sagittal vertical axis >5 cm. All patients had minimum 2 years' follow-up (N = 222). MCID was defined as 12.8 or more points of improvement in the Oswestry Disability Index. Up to 2 different etiologies for failure were allowed per patient.

RESULTS

We identified 78 cases (35%) where the patient failed to achieve MCID at long-term follow-up. A total of 82 identifiable causes were seen in these patients with 14 patients having multiple causes. In 6 patients, the etiology was unclear. The causes were subclassified as neurologic, medical, structural, under treatment, degenerative progression, traumatic, idiopathic, and floor effects. In 71% of cases, an identifiable cause was related to the spine, whereas in 35% the cause was not related to the spine.

CONCLUSIONS

Definable causes of failed MIS ASD surgery are often identifiable and similar to open surgery. In some cases the cause is treatable and structural. However, it is also common to see failure due to pathologies unrelated to the index surgery.

The impact of surgeon experience on perioperative complications and operative measures following thoracolumbar 3-column osteotomy for adult spinal deformity: overcoming the learning curve

OBJECTIVE

Posterior-based thoracolumbar 3-column osteotomy (3CO) is a formidable surgical procedure. Surgeon experience and case volume are known factors that influence surgical complication rates, but these factors have not been studied well in cases of adult spinal deformity (ASD). This study examines how surgeon experience affects perioperative complications and operative measures following thoracolumbar 3CO in ASD.

METHODS

A retrospective study was performed of a consecutive cohort of thoracolumbar ASD patients who underwent 3CO performed by the senior authors from 2006 to 2018. Multivariate analysis was used to assess whether experience (years of experience and/or number of procedures) is associated with perioperative complications, operative duration, and blood loss.

RESULTS

A total of 362 patients underwent 66 vertebral column resections (VCRs) and 296 pedicle subtraction osteotomies (PSOs). The overall complication rate was 29.4%, and the surgical complication rate was 8.0%. The rate of postoperative neurological deficits was 6.2%. There was a trend toward lower overall complication rates with greater operative years of experience (from 44.4% to 28.0%) (p = 0.115). Years of operative experience was associated with a significantly lower rate of neurological deficits (p = 0.027); the incidence dropped from 22.2% to 4.0%. The mean operative time was 310.7 minutes overall. Both increased years of experience and higher case numbers were significantly associated with shorter operative times (p < 0.001 and p = 0.001, respectively). Only operative years of experience was independently associated with operative times (p < 0.001): 358.3 minutes from 2006 to 2008 to 275.5 minutes in 2018 (82.8 minutes shorter). Over time, there was less deviation and more consistency in operative times, despite the implementation of various interventions to promote fusion and prevent construct failure: utilization of multiple-rod constructs (standard, satellite, and nested rods), bone morphogenetic protein, vertebroplasty, and ligament augmentation. Of note, the use of tranexamic acid did not significantly lower blood loss.

CONCLUSIONS

Surgeon years of experience, rather than number of 3COs performed, was a significant factor in mitigating neurological complications and improving quality measures following thoracolumbar 3CO for ASD. The 3- to 5-year experience mark was when the senior surgeon overcame a learning curve and was able to minimize neurological complication rates. There was a continuous decrease in operative time as the surgeon's experience increased; this was in concurrence with the implementation of additional preventative surgical interventions. Ongoing practice changes should be implemented and can be done safely, but it is imperative to self-assess the risks and benefits of those practice changes.

The Effect of Tobacco Smoking on Adverse Events Following Adult Complex Deformity Surgery: Analysis of 270 Patients From the Prospective, Multicenter Scoli-RISK-1 Study

STUDY DESIGN

Post-hoc analysis of a prospective, multicenter cohort study.

OBJECTIVE

To analyze the impact of smoking on rates of postoperative adverse events (AEs) in patients undergoing high-risk adult spine deformity surgery.

SUMMARY OF BACKGROUND DATA

Smoking is a known predictor of medical complications after adult deformity surgery, but the effect on complications, implant failure and other AEs has not been adequately described in prospective studies.

METHODS

Twenty-six patients with a history of current smoking were identified out of the 272 patients enrolled in the SCOLI-RISK-1 study who underwent complex adult spinal deformity surgery at 15 centers, with 2-year follow-up. The outcomes and incidence of AEs in these patients were compared to the nonsmoking cohort (n = 244) using univariate analysis, with additional multivariate regression to adjust for the effect of patient demographics, complexity of surgery, and other confounders.

RESULTS

The number of levels and complexity of surgery in both cohorts were comparable. In the univariate analysis, the rates of implant failure were almost double (odds ratio 2.28 [0.75-6.18]) in smoking group (n = 7; 26.9%)) that observed in the nonsmoking group (n = 34; 13.9%), but this was not statistically significant (P = 0.088). Surgery-related excessive bleeding (>4 L) was significantly higher in the smoking group (n = 5 vs. n = 9; 19.2% vs. 3.7%; OR 6.22[1.48 - 22.75]; P = 0.006). Wound infection rates and respiratory complications were similar in both groups. In the multivariate analysis, the smoking group demonstrated a higher incidence of any surgery-related AEs over 2 years (n = 13 vs. n = 95; 50.0% vs. 38.9%; OR 2.12 [0.88-5.09]) (P = 0.094).

CONCLUSION

In this secondary analysis of patients from the SCOLI-RISK-1 study, a history of smoking significantly increased the risk of excessive intraoperative bleeding and nonsignificantly increased the rate of implant failure or surgery-related AEs over 2 years. The authors therefore advocate a smoking cessation program in patients undergoing complex adult spine deformity surgery.

LEVEL OF EVIDENCE

2.

Less invasive spinal deformity surgery: the impact of the learning curve at tertiary spine care centers

OBJECTIVE

The past decade has seen major advances in techniques for treating more complex spinal disorders using minimally invasive surgery (MIS). While appealing from the standpoint of patient perioperative outcomes, a major impediment to adoption has been the significant learning curve in utilizing MIS techniques.

METHODS

Data were retrospectively analyzed from a multicenter series of adult spinal deformity surgeries treated at eight tertiary spine care centers in the period from 2008 to 2015. All patients had undergone a less invasive or hybrid approach for a deformity correction satisfying the following inclusion criteria at baseline: coronal Cobb angle ≥ 20°, sagittal vertical axis (SVA) > 5 cm, or pelvic tilt > 20°. Analyzed data included baseline demographic details, severity of deformity, surgical metrics, clinical outcomes (numeric rating scale [NRS] score and Oswestry Disability Index [ODI]), radiographic outcomes, and complications. A minimum follow-up of 2 years was required for study inclusion.

RESULTS

Across the 8-year study period, among 222 patients, there was a trend toward treating increasingly morbid patients, with the mean age increasing from 50.7 to 62.4 years (p = 0.013) and the BMI increasing from 25.5 to 31.4 kg/m2 (p = 0.12). There was no statistical difference in the severity of coronal and sagittal deformity treated over the study period. With regard to radiographic changes following surgery, there was an increasing emphasis on sagittal correction and, conversely, less coronal correction. There was no statistically significant difference in clinical outcomes over the 8-year period, and meaningful improvements were seen in all years (ODI range of improvement: 15.0-26.9). Neither were there statistically significant differences in major complications; however, minor complications were seen less often as the surgeons gained experience (p = 0.064). Operative time was decreased on average by 47% over the 8-year period.Trends in surgical practice were seen as well. Total fusion construct length was unchanged until the last year when there was a marked decrease in conjunction with a decrease in interbody levels treated (p = 0.004) while obtaining a higher degree of sagittal correction, suggesting more selective but powerful interbody reduction methods as reflected by an increase in the lateral and anterior column resection techniques being utilized.

CONCLUSIONS

The use of minimally invasive methods for adult spinal deformity surgery has evolved over the past decade. Experienced surgeons are treating older and more morbid patients with similar outcomes. A reliance on selective, more powerful interbody approaches is increasing as well.

Development and validation of risk stratification models for adult spinal deformity surgery

OBJECTIVE

Adult spinal deformity (ASD) surgery has a high rate of major complications (MCs). Public information about adverse outcomes is currently limited to registry average estimates. The object of this study was to assess the incidence of adverse events after ASD surgery, and to develop and validate a prognostic tool for the time-to-event risk of MC, hospital readmission (RA), and unplanned reoperation (RO).

METHODS

Two models per outcome, created with a random survival forest algorithm, were trained in an 80% random split and tested in the remaining 20%. Two independent prospective multicenter ASD databases, originating from the European continent and the United States, were queried, merged, and analyzed. ASD patients surgically treated by 57 surgeons at 23 sites in 5 countries in the period from 2008 to 2016 were included in the analysis.

RESULTS

The final sample consisted of 1612 ASD patients: mean (standard deviation) age 56.7 (17.4) years, 76.6% women, 10.4 (4.3) fused vertebral levels, 55.1% of patients with pelvic fixation, 2047.9 observation-years. Kaplan-Meier estimates showed that 12.1% of patients had at least one MC at 10 days after surgery; 21.5%, at 90 days; and 36%, at 2 years. Discrimination, measured as the concordance statistic, was up to 71.7% (95% CI 68%-75%) in the development sample for the postoperative complications model. Surgical invasiveness, age, magnitude of deformity, and frailty were the strongest predictors of MCs. Individual cumulative risk estimates at 2 years ranged from 3.9% to 74.1% for MCs, from 3.17% to 44.2% for RAs, and from 2.67% to 51.9% for ROs.

CONCLUSIONS

The creation of accurate prognostic models for the occurrence and timing of MCs, RAs, and ROs following ASD surgery is possible. The presented variability in patient risk profiles alongside the discrimination and calibration of the models highlights the potential benefits of obtaining time-to-event risk estimates for patients and clinicians.

Surgical correction of severe adult lumbar scoliosis (major curves ≥ 75°): retrospective analysis with minimum 2-year follow-up

OBJECTIVE

Prior reports have demonstrated the efficacy of surgical correction for adult lumbar scoliosis. Many of these reports focused on mild to moderate scoliosis. The authors' objective was to report their experience and to assess outcomes and complications after deformity correction for severe adult scoliosis.

METHODS

The authors retrospectively analyzed consecutive adult scoliosis patients with major thoracolumbar/lumbar (TL/L) curves ≥ 75° who underwent deformity correction at their institution. Those eligible with a minimum 2 years of follow-up were included. Demographic, surgical, coronal and sagittal plane radiographic measurements, and health-related quality of life (HRQL) scores were analyzed.

RESULTS

Among 26 potentially eligible patients, 22 (85%) had a minimum 2 years of follow-up (range 24-89 months) and were included in the study (mean age 57 ± 11 years; 91% women). The cohort comprised 16 (73%), 4 (18%), and 2 (9%) patients with adult idiopathic scoliosis, de novo degenerative scoliosis, and iatrogenic scoliosis, respectively. The surgical approach was posterior-only and multistage anterior-posterior in 18 (82%) and 4 (18%) patients, respectively. Three-column osteotomy was performed in 5 (23%) patients. Transforaminal and anterior lumbar interbody fusion were performed in 14 (64%) and 4 (18%) patients, respectively. All patients had sacropelvic fixation with uppermost instrumented vertebra in the lower thoracic spine (46% [10/22]) versus upper thoracic spine (55% [12/22]). The mean fusion length was 14 ± 3 levels. Preoperative major TL/L and lumbosacral fractional (L4-S1) curves were corrected from 83° ± 8° to 28° ± 13° (p < 0.001) and 34° ± 8° to 13° ± 6° (p < 0.001), respectively. Global coronal and sagittal balance significantly improved from 5 ± 4 cm to 1 ± 1 cm (p = 0.001) and 9 ± 8 cm to 2 ± 3 cm (p < 0.001), respectively. Pelvic tilt significantly improved from 33° ± 9° to 23° ± 10° (p < 0.001). Significant improvement in HRQL measures included the following: Scoliosis Research Society (SRS) pain score (p = 0.009), SRS appearance score (p = 0.004), and SF-12/SF-36 physical component summary (PCS) score (p = 0.026). Transient and persistent neurological deficits occurred in 8 (36%) and 2 (9%) patients, respectively. Rod fracture/pseudarthrosis occurred in 6 (27%) patients (supplemental rods were utilized more recently in 23%). Revisions were performed in 7 (32%) patients.

CONCLUSIONS

In this single-center surgical series for severe adult scoliosis (major curves ≥ 75°), a posterior-only or multistage anterior-posterior approach provided major curve correction of 66% and significant improvements in global coronal and sagittal spinopelvic alignment. Significant improvements were also demonstrated in HRQL measures (SRS pain, SRS appearance, and SF-12/SF-36 PCS). Complications and revisions were comparable to those of other reports involving less severe scoliosis. The results of this study warrant future prospective multicenter studies to further delineate outcomes and complication risks for severe adult scoliosis correction.

Risk, Recovery, and Clinical Impact of Neurological Complications in Adult Spinal Deformity Surgery

STUDY DESIGN

Multicenter retrospective case series.

OBJECTIVE

To report the risks, recovery, and clinical impact of neurological complications (NCs) in adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Although recent studies have reported the incidence of NCs in ASD surgery, few have addressed the recovery from and clinical impacts of NC.

METHODS

We reviewed records from a multicenter database for 285 consecutive surgically treated ASD patients who had reached a 2-year follow-up. NCs were categorized as sensory only or motor deficit (MD). Recovery was noted as none, partial, or complete, during hospitalization and at every postoperation visit. Uni- and multivariate risk analyses were performed to identify risk factors for MD.

RESULTS

NC developed in 29 (10%) patients within 30 days of surgery, of which 11 were permanent deficits (seven no recovery, and four partial recovery). MD developed in 14 (5%) patients, including one spinal cord injury. Seven MD patients required physical assistance at the latest follow-up. While NC patients experienced significant improvements in health-related quality of life at the 2-year follow-up, the health-related quality of life was significantly worse for the NC versus no-NC group at this time point. Univariate analyses revealed that Schwab-SRS types N and L, pelvic tilt, modified frailty index physical function, and an inferior SRS22 function domain at baseline were risk factors for MD. Among them, modified frailty index physical function, which represented a preoperative decline in activities of daily living, was identified as an independent risk factor for MD (OR: 4.0, 95% CI: 1.2-13.5, P = 0.03).

CONCLUSIONS

NC developed in 10% of ASD surgery patients, with permanent deficits occurring in 4%. Half of the patients who developed MD required physical assistance, which contributed to the inferior clinical outcomes. Surgical intervention should be considered before severe activities of daily living decline to prevent NCs.

LEVEL OF EVIDENCE

4.

Assessment and management of adult spinal deformities

Adult spinal deformity is a complex condition, increasing in prevalence, and occurring in a patient population in which it poses unique challenges. This review provides an overview of adult spinal deformity with a particular focus on its clinical evaluation, radiological assessment and classification, reviewing the current literature and amalgamating this with the authors' clinical experience.

SURGERY FOR ADULT SPINAL SCOLIOSIS: DO THE BENEFITS OUTWEIGH THE RISKS?

ABSTRACT Around 6% of the elderly population over 65 years of age are affected by adult spinal deformity (ASD). The increasing prevalence of ASD with aging has prompted discussion regarding the use of various techniques for its treatment, such as surgery and conservative treatment. The objective of this study is to investigate whether surgical treatment demonstrates significant benefits as compared to conservative treatment. A literature review was conducted, focusing on the most relevant papers on the topic published in the last five years. Surgical treatment, which costs an average of US$ 99,114 per procedure, enables almost instant improvement of the pain and disability of ASD. The rate of perioperative complications in ASD is approximately 7.5%, and the average improvement in back pain is 6.2 times higher in the surgical approach than in conservative treatment. In addition, the use of modern operative techniques, such as minimally invasive surgery (MIS), reduces the complications and greatly improves patients’ quality of life, compared to open surgery. Therefore, the expected benefits of surgical treatment meets the patient’s expectations by eliminating the pain caused by ASD. Although surgical treatment has a higher cost and a greater risk of complications, the use of minimally invasive techniques give the ASD patient a better quality of life. Level of evidence III; Non-Systematic Review.

[An age-stratified follow-up of complications and clinical benefit of posterior lumbar intervertebral fusion procedure in middle-aged and older patients]

Objective

To compare the complications and clinical scores of posterior lumbar intervertebral fusion (PLIF) in middle-aged and older patients of different ages, and to assess the risk of complications of PLIF in different ages, providing a reference for clinical treatment.

Methods

The clinical data of 1 136 patients, who were more than 55 years old and underwent PLIF between June 2013 and June 2016, were retrospectively analyzed. According to the age of patients undergoing surgery, they were divided into 3 groups as 55-64 years old, 65-74 years old, and ≥75 years old. The general characteristics, comorbidities, and surgical data of the three groups were compared, with comparison the morbidity of complications. According to the minimal clinical important difference (MCID), the improvement of patient's pain visual analogue scale (VAS) score and the Oswestry disability index (ODI) score were compared. Univariate logistic regression analysis was used to analyze the difference of complications and the improvement of VAS and ODI scores. Multivariate logistic regression analysis was performed for the risk factors of complications.

Results

There were significant differences in the number of surgical fusion segments and osteoporosis between groups ( P<0.05); there was no significant difference in gender, body mass index, operation time, preoperative American Society of Anesthesiologists (ASA) classification, and comorbidities between groups ( P>0.05). All patients were followed up 6-62 months with an average of 27.4 months. Among the results of postoperative complications, there were significant differences in the total incidence of intraoperative complications, systemic complications, minor complications, and the percentage of improvement of ODI score to MCID between groups ( P<0.05); but there was no significant difference in the total incidence of complications at the end of long-term follow-up and the percentage of improvement of VAS score to MCID between groups ( P>0.05). Univariate logistic regression analysis showed that after adjusting the confounding factors, there were significant differences in intraoperative complications and the percentage of improvement of ODI score to MCID between 55-64 and 65-74 years old groups ( P<0.05); systemic complications, minor complications, complications at the end of long-term follow-up, and the percentage of improvement of ODI score to MCID in ≥75 years old group were significantly different from those in the other two groups ( P<0.05). Multivariate logistic regression analysis showed that age was a risk factor for systemic complications, minor complications, and complications at the end of long-term follow-up. Except for age, long operation time was a risk factor for intraoperative complications, increased number of fusion segments was a risk factor for systemic complications, the number of comorbidities was a risk factor for minor complications, and osteoporosis was a risk factor for complications at the end of long-term follow-up.

Conclusion

The risk of surgical complications is higher in the elderly patients (≥75 years) with lumbar degenerative diseases than in the middle-aged and older patients (<75 years), while the improvements of postoperative VAS and ODI scores were similar. Under the premise of fully assessing surgical indications, PLIF has a positive effect on improving the elderly patients' quality of life.

Neurologic Injury in Complex Adult Spinal Deformity Surgery: Staged Multilevel Oblique Lumbar Interbody Fusion (MOLIF) Using Hyperlordotic Tantalum Cages and Posterior Fusion Versus Pedicle Subtraction Osteotomy (PSO)

STUDY DESIGN

A retrospective review of prospectively collected data.

OBJECTIVE

The aim of this study was to determine the safety of MOLIF versus PSO.

SUMMARY OF BACKGROUND DATA

Complex adult spinal deformity (CASD) represents a challenging cohort of patients. The Scoli-RISK-1 study has shown a 22.18% perioperative risk of neurological injury. Restoration of sagittal parameters is associated with good outcome in ASD. Pedicle subtraction osteotomies (PSO) is an important technique for sagittal balance in ASD but is associated with significant morbidity. The multilevel oblique lumbar interbody fusion (MOLIF) is an extensile approach from L1 to S1.

METHODS

Single surgeon series from 2007 to 2015. Prospectively collected data. Scoli-RISK-1 criteria were refined to only include stiff or fused spines otherwise requiring a PSO. Roentograms were examined preoperatively and 2 year postoperatively. Primary outcome measure was the motor decline in American Spinal Injury Association (ASIA) at hospital discharge, 6 weeks, 6 months, and 2 years. Demographics, blood loss, operative time, spinopelvic parameters, and spinal cord monitoring (SCM) events.

RESULTS

Sixty-eight consecutive patients were included in this study, with 34 patients in each Group. Group 1 (MOLIF) had a mean age 62.9 (45-81) and Group 2 (PSO) had a mean age of 66.76 years (47-79); 64.7% female versus PSO 76.5%; Body Mass Index (BMI) Group 1 (MOLIF) 28.05 and Group 2 (PSO) 27.17. Group 1 (MOLIF) perioperative neurological injury was 2.94% at discharge but resolved by 6 weeks. Group 2 (PSO) had five neurological deficits (14.7%) with no recovery by 2 years. There were four SCM events (SCM). In Group 1 (MOLIF), there was one event (2.94%) versus three events (8.88%) in Group 2 (PSO).

CONCLUSION

Staged MOLIF avoids passing neurological structures or retraction of psoas and lumbar plexus. It is safer than PSO in CASD with stiff or fused spines with a lower perioperative neurological injury profile. MOLIF have less SCM events, blood loss, and number of levels fused.

LEVEL OF EVIDENCE

3.

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

STUDY DESIGN

Narrative review.

OBJECTIVE

The prevalence of adult spinal deformity (ASD) has been cited anywhere between 2-32%, while the prevalence in the elderly population has been estimated at 68%. Neurologic complications following ASD surgery remains a concern. Previous literature reported incidence of neurologic complications varied between 1-10%, while non-neurologic complications reported were as high as 50%. To assess the incidence of neurologic deficits, complications, and outcomes following ASD surgery, an international group of spine deformity surgeons initiated a prospective, multicenter, international, observational study: Scoli-RISK-1.

METHODS

Two hundred seventy-two patients were enrolled from 15 centers with ASD having primary or revision surgery with a major Cobb≥80°, revision including an osteotomy, and/or a complex 3-column osteotomy. Patients had lower extremity muscle strength (LEMS) exams performed preoperatively and at specific time points through 2-year follow-up.

RESULTS

Preoperatively, 203 patients (74.9%) had no LEMS impairment (normal) and 68 (25.1%) had a LEMS of <50 (abnormal). Compared with baseline, 23.0% of all patients experienced a LEMS decline at discharge, with this rate decreasing to 17.1% at 6-weeks and to 9.9% at 6-months and remaining stable at 10.0% at 2-years.

CONCLUSION

This study revealed that a decline in LEMS after complex ASD surgery is common and more frequent than previously reported. We identified such a decline in 23.0% of patients at discharge, with neurologic function recovering over time to a decline of 10.0% at 2-years postoperatively. The Scoli-RISK-1 study revealed valuable information regarding the incidence, natural history, and prognosis of neurologic and non-neurologic complications following ASD surgery and provides useful information for patient counseling.

Postoperative changes in neurological function after 3-column osteotomy: risk factor analysis of 199 patients

OBJECTIVE

The authors evaluated the neurological outcomes of adult spinal deformity patients after 3-column osteotomy (3CO), including severity and long-term improvement of neurological complications, as well as risk factors for neurological deficit at 1 year postoperatively. Although 3CO is effective for correcting rigid spinal deformity, it is associated with a high complication rate. Neurological deficits, in particular, cause disability and dissatisfaction.

METHODS

The authors retrospectively queried a prospective database of adult spinal deformity patients who underwent vertebral column resection or pedicle subtraction osteotomy between 2004 and 2014 by one surgeon at a tertiary care center. The authors included 199 adults with at least 1-year follow-up. The primary outcome measure was change in lower-extremity motor scores (LEMSs), which were obtained preoperatively, within 2 weeks postoperatively, and at 6 and 12 months postoperatively. To identify risk factors for persistent neurological deficit, the authors compared patient and surgical characteristics with a declined LEMS at 12-month follow-up (n = 10) versus those with an improved/maintained LEMS at 12-month follow-up (n = 189).

RESULTS

At the first postoperative assessment, the LEMS had improved in 15% and declined in 10% of patients compared with preoperative scores. At the 6-month follow-up, 6% of patients continued to have a decline in LEMS, and 16% had improvement. At 12 months, LEMS had improved in 17% and declined in 5% of patients compared with preoperative scores. The only factor significantly associated with a decline in 12-month LEMS was high-grade spondylolisthesis as an indication for surgery (OR 13, 95% CI 3.2-56).

CONCLUSIONS

Although the LEMS declined in 10% of patients immediately after 3CO, at 12 months postoperatively, only 5% of patients had neurological motor deficits. A surgical indication of high-grade spondylolisthesis was the only factor associated with neurological deficit at 12 months postoperatively.