Evolution in Surgical Approach, Complications, and Outcomes in an Adult Spinal Deformity Surgery Multicenter Study Group Patient Population

Inflation-adjusted medicare physician reimbursement for adult spinal deformity surgery substantially declined from 2002 to 2020

PURPOSE

Physician fees for orthopaedic surgeons by the Centers for Medicare and Medicaid Services (CMS) are increasingly scrutinized. The present retrospective review aims to assess whether adult spinal deformity (ASD) surgeries are properly valued for Medicare reimbursement.

METHODS

Current Procedural Terminology (CPT) codes related to posterior fusion of spinal deformity of ≤ 6, 7-12, and ≥ 13 vertebral levels, as well as additional arthrodesis and osteotomy levels, were assessed for (1) Compound annual growth rate (CAGR) from 2002 to 2020, calculated using physician fee data from the CMS Physician Fee Schedule Look-Up Tool; and (2) work relative value units (RVUs) per operative minute, using data from the National Surgical Quality Improvement Program.

RESULTS

From 2002 to 2020, all CPT codes for ASD surgery had negative inflation-adjusted CAGRs (range, - 18.49% to - 27.66%). Mean physician fees for spinal fusion declined by 26.02% (CAGR, - 1.66%) in ≤ 6-level fusion, 27.91% (CAGR, - 1.80%) in 7- to 12-level fusion, and 28.25% (CAGR, - 1.83%) ≥ 13-level fusion. Fees for both 7-12 (P < 0.00001) and ≥ 13 levels (P < 0.00001) declined more than those for fusion of ≤ 6 vertebral levels. RVU per minute was lower for 7- to 12-level and ≥ 13-level (P < 0.00001 for both) ASD surgeries than for ≤ 6-level.

CONCLUSIONS

Reimbursement for ASD surgery declined overall. CAGR for fusions of ≥ 7 levels were lower than those for fusions of ≤ 6 levels. For 2012-2018, ≥ 7-level fusions had lower RVU per minute than ≤ 6-level fusions. Revaluation of Medicare reimbursement for longer-level ASD surgeries may be warranted.

LEVEL OF EVIDENCE

III.

Impact of multi-rod reinforcement on rod fractures in adult spinal deformity: A retrospective case series with a minimum follow up of 5 years

BACKGROUND

This study aimed to determine the impact of the multi-rod construct on rod fractures over a minimum follow-up period of five years in comparison to that with the conventional two-rod construct using the same technique, rod composition, and rod reinforcement method.

METHODS

Data were retrospectively retrieved from a prospectively collected, single-center database. Consecutive patients >50 years of age who underwent thoracopelvic corrective fusion with planned two-stage anterior-posterior surgery and were followed up for at least five years were included in this study. The incidence of rod fracture in the conventional two-rod and multi-rod groups was investigated.

RESULTS

A total of 58 patients (mean age, 68.9 years) were included in this study (follow-up rate, 73.4 %). Rod fracture was identified in 25 patients (43.1 %), within an average period of 25.1 months. The incidence of rod fracture in the multi-rod group was significantly lower than that in the two-rod group. However, there was no significant difference in the time to rod fracture between the two groups. Reinforcement of the multi-rod to the distal portion of the connector of the iliac screw had the lowest fracture rate and no cases of reoperation.

CONCLUSIONS

The incidence of rod fracture was significantly lower using multi-rod reinforcement, but the timing of rod fracture did not differ, compared to that with the two-rod construct using the same surgical technique and rod material. Multi-rod reinforcement covering the distal portion of the iliac screw is recommended to reduce the risk of fracture and reoperation.

Patient-Centered Outcomes Following Prone Lateral Single-Position Approach to Same-Day Circumferential Spine Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVE

Evaluate surgical characteristics and postoperative 2-year results of the PL approach to spinal fusion.

SUMMARY OF BACKGROUND DATA

Prone-lateral(PL) single positioning has recently gained popularity in spine surgery due to lower blood loss and operative time but has yet to be examined for other notable outcomes, including realignment and patient-reported measures.

MATERIALS AND METHODS

We included circumferential spine fusion patients with a minimum one-year follow-up. Patients were stratified into groups based on undergoing PL approach versus same-day staged (Staged). Mean comparison tests identified differences in baseline parameters. Multivariable logistic regression, controlling for age, levels fused, and Charlson Comorbidity Index were used to determine the influence of the approach on complication rates, radiographic and patient-reported outcomes up to two years.

RESULTS

One hundred twenty-two patients were included of which 72(59%) were same-day staged and 50(41%) were PL. PL patients were older with lower body mass index (both P <0.05). Patients undergoing PL procedures had lower estimated blood loss and operative time (both P <0.001), along with fewer osteotomies (63% vs. 91%, P <0.001). This translated to a shorter length of stay (3.8 d vs. 4.9, P =0.041). PL procedures demonstrated better correction in both PT (4.0 vs. -0.2, P =0.033 and pelvic incidence and lumbar lordosis (-3.7 vs. 3.1, P =0.012). PL procedures were more likely to improve in GAP relative pelvic version (OR: 2.3, [1.5-8.8]; P =0.003]. PL patients suffered lesser complications during the perioperative period and greater improvement in NRS-Back (-6.0 vs. -3.3, P =0.031), with less reoperations (0.0% vs. 4.8%, P =0.040) by two years.

CONCLUSIONS

Patients undergoing PL single-position procedures received less invasive procedures with better correction of pelvic compensation, as well as earlier discharge. The prone lateral cohort also demonstrated greater clinical improvement and a lower rate of reoperations by two years following spinal corrective surgery.

LEVEL OF EVIDENCE

Level-III.

Combined Anterior-Posterior vs. Posterior-Only Approach in Adult Spinal Deformity Surgery: Which Strategy Is Superior?

Introduction: Whether a combined anterior-posterior (AP) approach offers additional benefits over the posterior-only (P) approach in adult spinal deformity (ASD) surgery remains unknown. In a cohort of patients undergoing ASD surgery, we compared the combined AP vs. the P-only approach in: (1) preoperative/perioperative variables, (2) radiographic measurements, and (3) postoperative outcomes. Methods: A single-institution, retrospective cohort study was performed for patients undergoing ASD surgery from 2009 to 2021. Inclusion criteria were ≥5-level fusion, sagittal/coronal deformity, and 2-year follow-up. The primary exposure was the operative approach: a combined AP approach or P alone. Postoperative outcomes included mechanical complications, reoperation, and minimal clinically important difference (MCID), defined as 30% of patient-reported outcome measures (PROMs). Multivariable linear regression was controlled for age, BMI, and previous fusion. Results: Among 238 patients undergoing ASD surgery, 34 (14.3%) patients underwent the AP approach and 204 (85.7%) underwent the P-only approach. The AP group consisted mostly of anterior lumbar interbody fusion (ALIF) at L5/S1 (73.5%) and/or L4/L5 (38.0%). Preoperatively, the AP group had more previous fusions (64.7% vs. 28.9%, p < 0.001), higher pelvic tilt (PT) (29.6 ± 11.6° vs. 24.6 ± 11.4°, p = 0.037), higher T1 pelvic angle (T1PA) (31.8 ± 12.7° vs. 24.0 ± 13.9°, p = 0.003), less L1-S1 lordosis (-14.7 ± 28.4° vs. -24.3 ± 33.4°, p < 0.039), less L4-S1 lordosis (-25.4 ± 14.7° vs. 31.6 ± 15.5°, p = 0.042), and higher sagittal vertical axis (SVA) (102.6 ± 51.9 vs. 66.4 ± 71.2 mm, p = 0.005). Perioperatively, the AP approach had longer operative time (553.9 ± 177.4 vs. 397.4 ± 129.0 min, p < 0.001), more interbodies placed (100% vs. 17.6%, p < 0.001), and longer length of stay (8.4 ± 10.7 vs. 7.0 ± 9.6 days, p = 0.026). Radiographically, the AP group had more improvement in T1PA (13.4 ± 8.7° vs. 9.5 ± 8.6°, p = 0.005), L1-S1 lordosis (-14.3 ± 25.6° vs. -3.2 ± 20.2°, p < 0.001), L4-S1 lordosis (-4.7 ± 16.4° vs. 3.2 ± 13.7°, p = 0.008), and SVA (65.3 ± 44.8 vs. 44.8 ± 47.7 mm, p = 0.007). These outcomes remained statistically significant in the multivariable analysis controlling for age, BMI, and previous fusion. Postoperatively, no significant differences were found in mechanical complications, reoperations, or MCID of PROMs. Conclusions: Preoperatively, patients undergoing the combined anterior-posterior approach had higher PT, T1PA, and SVA and lower L1-S1 and L4-S1 lordosis than the posterior-only approach. Despite increased operative time and length of stay, the anterior-posterior approach provided greater sagittal correction without any difference in mechanical complications or PROMs.

Impact of congestive heart failure on patients undergoing lumbar spine fusion for adult spine deformity

Background

With the increasing amount of elective spine fusion patients presenting with cardiac disease and congestive heart failure, it is becoming difficult to assess when it is safe to proceed with surgery. Assessing the severity of heart failure (HF) through ejection fraction may provide insight into patients' short- and long-term risks.

Purpose

The purpose of this study was to assess the severity of HF on perioperative outcomes of spine fusion surgery patients.

Study Design/Setting

This was a retrospective cohort study of the PearlDiver database.

Patient Sample

We enrolled 670,526 patients undergoing spine fusion surgery.

Outcome Measures

Thirty-day and 90-day complication rates, discharge destination, length of stay (LOS), physician reimbursement, and hospital costs.

Methods

Patients undergoing elective spine fusion surgery were isolated and stratified by preoperative HF with preserved ejection fraction (P-EF) or reduced ejection fraction (R-EF) (International Classification of Diseases-9: 428.32 [chronic diastolic HF] and 428.22 [chronic systolic HF]). Means comparison tests (Chi-squared and independent samples t-tests, as appropriate) compared differences in demographics, diagnoses, comorbidities, procedural characteristics, LOS, 30-day and 90-day complication outcomes, and total hospital charges between those diagnosed with P-EF and those not R-EF. Binary logistic regression assessed the odds of complication associated with HF, controlling for levels fused (odds ratio [OR] [95% confidence interval]). Statistical significance was set at P < 0.05.

Results

Totally 670,526 elective spine fusion patients were included. Four thousand and seventy-seven were diagnosed with P-EF and 2758 R-EF. Overall, P-EF patients presented with higher rates of morbid obesity, chronic kidney disease, chronic obstructive pulmonary disease, diabetes mellitus, and hypertension (all P < 0.001). In relation to No-HF, P-EF patients had higher rates of 30-day major complications including pulmonary embolism, pneumonia, cerebrovascular accident (CVA), myocardial infarctions (MI), sepsis, and death (all P < 0.001). Furthermore, P-EF was associated significantly with increased odds of pneumonia (OR: 2.07 [1.64-2.56], P < 0.001) and sepsis (OR: 2.09 [1.62-2.66], P < 0.001). Relative to No-HF, R-EF was associated with significantly higher odds of MI (OR: 3.66 [2.34-5.47]), CVA (OR: 2.70 [1.67-4.15]), and pneumonia (OR: 1.85 [1.40-2.40]) (all P < 0.001) postoperative within 30 days. Adjusting for prior history of MI, CAD, and the presence of a pacemaker R-EF was a significant predictor of an MI 30 days postoperatively (OR: 2.2 [1.14-4.32], P = 0.021). Further adjusting for history of CABG or stent placement, R-EF was associated with higher odds of CVA (OR: 2.11 [1.09-4.19], P = 0.028) and MI (OR: 2.27 [1.20-4.43], P = 0.013).

Conclusions

When evaluating the severity of HF before spine surgery, R-EF was associated with a higher risk of major complications, especially the occurrence of a myocardial infarction 30 days postoperatively. During preoperative risk assessment, congestive HF should be considered thoroughly when thinking of postoperative outcomes with emphasis on R-EF.

The use of lateral lumbar interbody fusion for identifying adult patients with spinal deformities treatable by short corrective fusion in 2-stage surgery

BACKGROUND

To investigate and compare the surgical outcomes of short and thoracopelvic corrective fusion with our two-stage technique using lateral lumbar interbody fusion (LLIF) and posterior open surgery.

METHODS

Consecutive patients with adult spinal deformities who underwent a planned two-stage anterior-posterior surgery, using LLIF for the first stage and posterior open corrective fusion for the second stage, with a minimum of 2 years of follow-up were included. Patients who underwent lumbar or lumbosacral corrective fusion and thoracopelvic corrective fusion were categorized into the short group and thoracopelvic groups, respectively. We investigated the spinopelvic parameters and patient-reported outcome measurements.

RESULTS

Seventy-four consecutive patients (8 men, 66 women; average age, 70.0 years) were included. Ten patients underwent short corrective fusion following significant improvements in the symptoms and radiographic parameters post-LLIF. Several preoperative spinopelvic parameters were better in the short group. Compared to the thoracopelvic group, those who underwent short fusion had a poorer alignment 2 years postoperatively but with comparable results and a significantly higher function score on the Scoliosis Research Society-22 r (SRS-22r) questionnaire. The mean Oswestry Disability Index and SRS-22r scores significantly improved during the 2-year postoperative follow-up in both the groups.

CONCLUSIONS

Short corrective fusion can be considered in patients whose symptoms and radiographic parameters significantly improve following LLIF. Patients who undergo short fusion with LLIF application have poorer alignment than those who undergo thoracopelvic fusion 2 years postoperatively; however, the results are comparable, and the function score is significantly improved.

Association Between the Bone Density of Posterior Fusion Mass and Mechanical Complications After Thoracolumbar Three-Column Osteotomy for Adult Spinal Deformity

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

To assess the relationship of fusion mass bone density on computed tomography (CT) and the development of rod fractures (RFs) and proximal junctional kyphosis (PJK).

SUMMARY OF BACKGROUND DATA

Few studies have evaluated the relationship of fusion mass bone density to mechanical complications.

MATERIALS AND METHODS

A retrospective review of adult spinal deformity patients who underwent thoracolumbar three-column osteotomy from 2007 to 2017 was performed. All patients underwent routine 1-year CT imaging and had at least 24 months follow-up. Posterior fusion mass bone density was evaluated by measuring hounsfield unit (HU) on CT in three different regions [upper instrumented vertebra (UIV), lower instrumented vertebra, and osteotomy site], and were compared between patients with and without mechanical complications.

RESULTS

A total of 165 patients (63.2 years, 33.5% male) were included. Overall PJK rate was 18.8%, and 35.5% of these underwent PJK revision. There was significantly lower density of posterior fusion mass at the UIV in patients who experienced PJK compared with patients without PJK (431.5HU vs. 537.4HU, P =0.026). Overall RF rate was 34.5% and 61.4% of these underwent revision for RFs. Among 57 patients with RFs, 71.9% had pseudarthrosis. Fusion mass density did not differ between patients with or without RFs. However, in RF patients with pseudarthrosis, there was significantly higher bone mass density near the osteotomy compared with those without pseudarthrosis (515.7HU vs. 354.2HU, P =0.012). There were no differences in radiographic sagittal measures between the patients with and without RF or PJK.

CONCLUSIONS

Patients with PJK tend to have less dense posterior fusion mass at the UIV. Fusion mass density does not correlate with RF, but greater bone density near the osteotomy was correlated with accompanying pseudarthrosis in patients with RFs. Assessing density of posterior fusion mass on CT may be helpful in assessing risk for PJK and provide insight as to the causes of RFs.

Risk of Dislocation and Revision Following Primary Total Hip Arthroplasty in Patients With Prior Lumbar Fusion With Spinopelvic Fixation

BACKGROUND

The effect of spinopelvic fixation in addition to lumbar spinal fusion (LSF) on dislocation/instability and revision in patients undergoing primary total hip arthroplasty (THA) has not been reported previously.

METHODS

The PearlDiver Research Program was used to identify patients aged 30 and above undergoing primary THA who received (1) THA only, (2) THA with prior single-level LSF, (3) THA with prior 2-5 level LSF, or (4) THA with prior LSF with spinopelvic fixation. The incidence of THA revision and dislocation/instability was compared through logistic regression and Chi-squared analysis. All regressions were controlled for age, gender, and Elixhauser Comorbidity Index (ECI).

RESULTS

Between 2010 and 2018, 465,558 patients without history of LSF undergoing THA were examined and compared to 180 THA patients with prior spinopelvic fixation, 5,299 with prior single-level LSF, and 1,465 with prior 2-5 level LSF. At 2 years, 7.8% of THA patients with prior spinopelvic fixation, 4.7% of THA patients with prior 2-5 level LSF, 4.2% of THA patients with prior single-level LSF, and 2.2% of THA patients undergoing only THA had a dislocation event or instability (P < .0001). After controlling for length of fusion, pelvic fixation itself was associated with higher independent risk of revision (at 2 years: 2-5 level LSF + spinopelvic fixation: aHR = 3.15, 95% CI 1.77-5.61, P < .0001 vs 2-5 level LSF with no spinopelvic fixation: aOR = 1.39, 95% CI 1.10-1.76, P < .0001).

CONCLUSION

At 2 years, spinopelvic fixation in THA patients were associated with a greater than 3.5-fold increase in hip dislocation risk compared to those without LSF, and an over 2-fold increase in THA revision risk compared to those with LSF without spinopelvic fixation.

LEVEL OF EVIDENCE

III.

Teleexercise for geriatric patients with failed back surgery syndrome

Introduction

Failed back surgery syndrome (FBSS) is defined as back pain which either persists after attempted surgical intervention or originates after a spine surgery. There is a high risk of perioperative morbidity and a high likelihood of extensive revision surgery in geriatric patients with FBSS or post-laminectomy foraminal stenosis.

Methods

There is a need for less invasive methodologies for the treatment of FBSS, such as patient-tailored exercise training, with attention to the cost and special needs of the geriatric patients with FBSS. This commentary will provide some background regarding teleexercise (utilizing an internet-based platform for the provision of exercise-related care) for FBSS and will propose three exercises which are easy to administer over online-based platforms and can be the subject of future investigation.

Results

Given the documented benefits of regular rehabilitative exercises for patients with FBSS, the high cost of face-to-face services, and the need for infection mitigation in the wake of the COVID-19 Pandemic, teleexercise may be a practical and cost-beneficial method of exercise delivery, especially for geriatric patients with limitations in mobility and access to care. It should be noted that, prescription of these exercises should be done after face-to-face evaluation by the physician and careful evaluation for any “red flag” symptoms.

Conclusion

In this commentary, we will suggest three practical exercise training methodologies and discuss the benefits of teleexercise for geriatric patients with FBSS. Future research should aim to assess the efficacy of these exercises, especially when administered through telehealth platforms.

The Clinical Impact of Failing to Achieve Ideal Proportional Realignment in Adult Spinal Deformity Patients

SUMMARY OF BACKGROUND DATA

The impact of not achieving ideal realignment in the global alignment and proportion (GAP) score in adult spinal deformity (ASD) correction on clinical outcomes is understudied at present.

OBJECTIVE

To identify the clinical impact of failing to achieve GAP proportionality in ASD surgery.

STUDY DESIGN

Retrospective cohort.

METHODS

Operative ASD patients with fusion to S1/pelvis and with pre-(BL) and 2-year (2Y) data were included. Patients were assessed for matching their 6-week (6W) age-adjusted alignment goals. 1 Patients were stratified by age-adjusted match at 6W postoperatively (Matched) and 6W GAP proportionality (proportioned: GAP-P; moderately disproportioned: GAP-MD; severely disproportioned: GAP-SD). Groups were assessed for differences in demographics, surgical factors, radiographic parameters, and complications occurring by 2Y. Multivariable logistic regression was used to assess independent effects of not achieving GAP proportionality on postoperative outcomes for Matched and Unmatched patients.

RESULTS

Included: One hundred twenty three ASD patients. At baseline, 39.8% were GAP-SD, and 12.2% GAP-SD at 6W. Of 123 patients, 51.2% (n =63) had more than or equal to one match at 6W. GAP-SD rates did not differ by being Matched or Unmatched ( P = 0.945). GAP-SD/Unmatched patients had higher rates of reoperation, implant failure, and PJF by 2Y postop (all P <0.05). Regressions controlling for age at BL, levels fused, and CCI, revealed 6W GAP-SD/Unmatched patients had higher odds of reoperation (OR: 54 [3.2-899.9]; P =0.005), implant failure (OR: 6.9 [1.1-46.1]; P =0.045), and PJF (OR: 30.1 [1.4-662.6]; P =0.031). Compared to GAP-P or GAP-MD patients, GAP-SD/ Matched patients did not have higher rates of reoperation, implant failure, or junctional failure (all P >0.05). The regression results for both Matched and Unmatched cohorts were consistent when proportionality was substituted by the continuous GAP score.

CONCLUSION

In ASD patients who meet age-adjusted realignment goals, GAP proportionality does not significantly alter complication rates. However, GAP proportionality remains an important consideration in patients with sub-optimal age- adjusted alignment. In these cases, severe global disproportion is associated with higher rates of reoperation, implant failure, rod fracture, and junctional failure.

Evolution of Proximal Junctional Kyphosis and Proximal Junctional Failure Rates Over 10 Years of Enrollment in a Prospective Multicenter Adult Spinal Deformity Database

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to investigate the evolution of proximal junctional kyphosis (PJK) rate over 10-year enrollment period within a prospective database.

SUMMARY OF BACKGROUND DATA

PJK is a common complication following adult spinal deformity (ASD) surgery and has been intensively studied over the last decade.

METHODS

Patients with instrumentation extended to the pelvis and minimum 2-year follow-up were included. To investigate evolution of PJK/proximal junctional failure (PJF) rate, a moving average of 321 patients was calculated across the enrollment period. Logistic regression was used to investigate the association between the date of surgery (DOS) and PJK and/or PJF. Comparison of PJK/PJF rates, demographics, and surgical strategies was performed between the first and second half of the cohort.

RESULTS

A total of 641 patients met inclusion criteria (age: 64±10 years, 78.2% female, body mass index: 28.3±5.7). The overall rate of radiographic PJK at 2 years was 47.9%; 12.9% of the patients developed PJF, with 31.3% being revised within 2-year follow-up. Stratification by DOS produced two halves. Between these two periods, rate of PJK and PJF demonstrated nonsignificant decrease (50.3%-45.5%, P =0.22) and (15.0%-10.9%, P =0.12), respectively. Linear interpolation suggested a decrease of 1.2% PJK per year and 1.0% for PJF. Patients enrolled later in the study were older and more likely to be classified as pure sagittal deformity ( P <0.001). There was a significant reduction in the use of three-column osteotomies ( P <0.001), an increase in anterior longitudinal ligament release ( P <0.001), and an increase in the use of PJK prophylaxis (31.3% vs 55.1%). Logistical regression demonstrated no significant association between DOS and radiographic PJK ( P =0.19) or PJF ( P =0.39).

CONCLUSION

Despite extensive research examining risk factors for PJK/PJF and increasing utilization of intraoperative PJK prophylaxis techniques, the rate of radiographic PJK and/or PJF did not significantly decrease across the 10-year enrollment period of this ASD database.

Combined anterior-posterior versus all-posterior approaches for adult spinal deformity correction: a matched control study

PURPOSE

Anterior approaches are gaining popularity for adult spinal deformity (ASD) surgeries especially with the introduction of hyperlordotic cages and improvement in MIS techniques. Combined Approaches provide powerful segmental sagittal correction potential and increase the surface area available for fusion in ASD surgery, both of which would improve overall. This is the first study directly comparing surgical outcomes between combined anterior-posterior approaches and all-posterior approach in a matched ASD population.

METHODS

This is a retrospective matched control cohort analysis with substitution using a multicenter prospectively collected ASD data of patients with > 2 year FU. Matching criteria include: age, American Society of Anesthesiologists Score, Lumbar Cobb angle, sagittal deformity (Global tilt) and ODI.

RESULTS

In total, 1024 ASD patients were available for analysis. 29 Combined Approaches patients met inclusion criteria, and only 22 could be matched (1:2 ratio). Preoperative non-matched demographical, clinical, surgical and radiological parameters were comparable between both groups. Combined approaches had longer surgeries (548 mns vs 283) with more blood loss (2850 ml vs 1471) and needed longer ICU stays (74 h vs 27). Despite added morbidity, they had comparable complication rates but with significantly less readmissions (9.1% vs 38.1%) and reoperations (18.2% vs 43.2%) at 2 years. Combined Approaches achieved more individualised and harmonious deformity correction initially. At the 2 years control, Combined Approaches patients reported better outcomes as measured by COMI and SRS scores. This trend was maintained at 3 years.

CONCLUSION

Despite an increased initial surgical invasiveness, combined approaches seem to achieve more harmonious correction with superior sagittal deformity control; they need fewer revisions and have improved long-term functional outcomes when compared to all-posterior approaches for ASD deformity correction.

Assessment of Adult Spinal Deformity Complication Timing and Impact on 2-Year Outcomes Using a Comprehensive Adult Spinal Deformity Classification System

STUDY DESIGN

Retrospective review of prospectively collected multicenter registry data.

OBJECTIVE

To identify rates and timing of postoperative complications in adult spinal deformity (ASD) patients, the impact of complication type and timing on health related quality of life (HRQoL) outcomes, and the impact of complication timing on readmission and reoperation rates. Better understanding of complication timing and impact on HRQoL may improve patient selection, preoperative counseling, and postoperative complication surveillance.

SUMMARY OF BACKGROUND DATA

ASD is common and associated with significant disability. Surgical correction is often pursued, but is associated with high complication rates. The International Spine Study Group, AO Spinal Deformity Forum, and European Spine Study Group have developed a new complication classification system for ASD (ISSG-AO spine complications classification system).

METHODS

The ISSG-AO spine complications classification system was utilized to assess complications occurring over the 2-year postoperative time period amongst a multicenter, prospectively enrolled cohort of patients who underwent surgery for ASD. Kaplan-Meier survival curves were established for each complication type. Propensity score matching was performed to adjust for baseline disability and comorbidities. Associations between each complication type and HRQoL, and reoperation/readmission and complication timing, were assessed.

RESULTS

Of 584 patients meeting inclusion criteria, cardiopulmonary, gastrointestinal, infection, early adverse events, and operative complications contributed to a rapid initial decrease in complication-free survival. Implant-related, radiographic, and neurologic complications substantially decreased long-term complication-free survival. Only radiographic and implant-related complications were significantly associated with worse 2-year HRQoL outcomes. Need for readmission and/or reoperation was most frequent among those experiencing complications after postoperative day 90.

CONCLUSION

Surgeons should recognize that long-term complications have a substantial negative impact on HRQoL, and should carefully monitor for implant-related and radiographic complications over long-term follow-up.Level of Evidence: 4.

Evolution of Complex Spine Surgery in Neurosurgery: From Big to Minimally Invasive Surgery for the Treatment of Spinal Deformity

Spinal instrumentation for adult spinal deformity dates back to the surgical correction of secondary complications from infectious processes, such as Pott's disease and poliomyelitis [1]. With the population aging at a longer life expectancy today, advanced degenerative spinal diseases and idiopathic scoliosis supersede as the most common causes of adult spinal deformity. Correction of the thoracolumbar malignment, specifically, has rapidly evolved with the burgeoning success of spinal instrumentation. The objective of this chapter is to review the metamorphosis of operative principles for adult thoracolumbar deformity, from aggressive osteotomies in the posterior bony elements to minimally invasive surgery (MIS) at the intervertebral disc space.

Perioperative Predictive Factors for Positive Outcomes in Spine Fusion for Adult Deformity Correction

Purpose: Identifying perioperative factors that may influence the outcomes of long spine fusion for the treatment of adult deformity is key for tailored surgical planning and targeted informed consent. The aim of this study was to analyze the association between demographic or perioperative factors and clinical outcomes 2 years after long spine fusion for the treatment of adult deformity. Methods: This study is a multivariate analysis of retrospectively collected data. All patients who underwent long fusion of the lumbar spine for adult spinal deformity (January 2016–June 2019) were included. The outcomes of interest were the Oswestry disability index (ODI), visual analogic scale (VAS) preoperatively and at 1 and 2 years’ follow up, age, body mass index, American Society of Anaesthesiologists (ASA) score, upper and lowest instrumented vertebrae (UIV and LIV, respectively), length of surgery, estimated blood loss, and length of hospital stay. Results: Data from 192 patients were available. The ODI at 2 years correlated weakly to moderately with age (r = 0.4), BMI (r = 0.2), ASA (r = 0.3), and LIV (r = 0.2), and strongly with preoperative ODI (r = 0.6). The leg VAS at 2 years moderately correlated with age (r = 0.3) and BMI (r = 0.3). Conclusion: ODI and VAS at 2 years’ follow-up had no to little association to preoperative age, health status, LIV, or other peroperative data, but showed a strong correlation with preoperative ODI and pain level.

Comparison of surgical invasiveness and morbidity of adult spinal deformity surgery to other major operations

BACKGROUND CONTEXT

Adult spinal deformity (ASD) surgeries are complex, involving long operative times and surgical morbidity. It is currently unclear how the invasiveness of ASD surgery compares to other major operations.

PURPOSE

To: (1) develop a quantitative score of surgical morbidity and invasiveness, and (2) compare this score between ASD surgery and other major operations.

STUDY DESIGN

Retrospective review of prospectively collected data.

PATIENT SAMPLE

A prospective surgical registry was used to identify all patients undergoing ASD surgery involving ≥ 7 segments. Seventeen additional procedures were included: coronary artery bypass grafting (CABG), pancreatectomy, and esophagectomy, among others.

OUTCOME MEASURES

Perioperative factors (operative time, transfusions, ventilation) and complications were collected and combined with a previously validated Postoperative Morbidity Survey to create a Surgical Invasiveness and Morbidity Score (SIMS).

METHODS

Computed scores were compared across surgeries using Welch's t-test. Multiple linear regression modeling was used to compare the SIMS of major surgeries relative to ASD while controlling for patient demographics and comorbidities.

RESULTS

A total of 1,245,282 surgical patients were included, 4,656 of which underwent ASD surgery. After multiple regression modeling controlling for patient demographics and comorbidities, ASD surgery ranked fourth in SIMS. ASD surgery had a significantly greater SIMS than 13 other major procedures including 6th esophagectomy (adjusted mean difference=-0.05, 95%CI -0.01-0.09, p<.001), 8th pancreatectomy (-0.40, 0.37-0.44, p<.001), 11th craniotomy for tumor (-1.01, 0.98-1.04, p<.001), and 12th sacral chordoma resection (-1.31, 1.26-1.37, p<.001).

CONCLUSIONS

ASD surgery was associated with significantly greater SIMS than many other major operations, even when controlling for important perioperative factors. These data have implications for patient counseling, resource allocation, and informed consent.

A BMP/Activin A Chimera Induces Posterolateral Spine Fusion in Nonhuman Primates at Lower Concentrations Than BMP-2

BACKGROUND

Supraphysiologic bone morphogenetic protein (BMP)-2 concentrations are required to induce spinal fusion. In this study, a BMP-2/BMP-6/activin A chimera (BV-265), optimized for BMP receptor binding, delivered in a recombinant human collagen:CDHA [calcium-deficient hydroxyapatite] porous composite matrix (CM) or bovine collagen:CDHA granule porous composite matrix (PCM), engineered for optimal BV-265 retention and guided tissue repair, was compared with BMP-2 delivered in a bovine absorbable collagen sponge (ACS) wrapped around a MASTERGRAFT Matrix (MM) ceramic-collagen rod (ACS:MM) in a nonhuman primate noninstrumented posterolateral fusion (PLF) model.

METHODS

In vivo retention of 125I-labeled-BV-265/CM or PCM was compared with 125I-labeled-BMP-2/ACS or BMP-2/buffer in a rat muscle pouch model using scintigraphy. Noninstrumented PLF was performed by implanting CM, BV-265/CM, BV-265/PCM, or BMP-2/ACS:MM across L3-L4 and L5-L6 or L3-L4-L5 decorticated transverse processes in 26 monkeys. Computed tomography (CT) images were acquired at 0, 4, 8, 12, and 24 weeks after surgery, where applicable. Manual palpation, μCT (microcomputed tomography) or nCT (nanocomputed tomography), and histological analysis were performed following euthanasia.

RESULTS

Retention of 125I-labeled-BV-265/CM was greater than BV-265/PCM, followed by BMP-2/ACS and BMP-2/buffer. The CM, 0.43 mg/cm3 BMP-2/ACS:MM, and 0.05 mg/cm3 BV-265/CM failed to generate PLFs. The 0.15-mg/cm3 BV-265/CM or 0.075-mg/cm3 BV-265/PCM combinations were partially effective. The 0.25-mg/cm3 BV-265/CM and 0.15 and 0.3-mg/cm3 BV-265/PCM combinations generated successful 2-level PLFs at 12 and 24 weeks.

CONCLUSIONS

BV-265/CM or PCM can induce fusion in a challenging nonhuman primate noninstrumented PLF model at substantially lower concentrations than BMP-2/ACS:MM.

CLINICAL RELEVANCE

BV-265/CM and PCM represent potential alternatives to induce PLF in humans at substantially lower concentrations than BMP-2/ACS:MM.

Novel Applications of Spinal Navigation in Deformity and Oncology Surgery-Beyond Screw Placement

Computer-assisted navigation has made a major impact on spine surgery, providing surgeons with technological tools to safely place instrumentation anywhere in the spinal column. With advances in intraoperative image acquisition, registration, and processing, many surgeons are now using navigation in their practices. The incorporation of navigation into the workflow of surgeons continues to expand with the evolution of minimally invasive techniques and robotic surgery. While numerous investigators have demonstrated the benefit of navigation for improving the accuracy of instrumentation, few have reported applying this technology to other aspects of spine surgery. Surgeries to correct spinal deformities and resect spinal tumors are technically demanding, incorporating a wide range of techniques not only for instrumentation placement but also for osteotomy planning and executing the goals of surgery. Although these subspecialties vary in their objectives, they share similar challenges with potentially high complications, invasiveness, and consequences of failed execution. Herein, we highlight the utility of using spinal navigation for applications beyond screw placement: specifically, for planning and executing osteotomies and guiding the extent of tumor resection. A narrative review of the work that has been done is supplemented with illustrative cases demonstrating these applications.

Safety of lateral access to the concave side for adult spinal deformity

OBJECTIVE

Minimally invasive surgery (MIS) techniques, particularly lateral lumbar interbody fusion (LLIF), have become increasingly popular for adult spinal deformity (ASD) correction. Much discussion has been had regarding theoretical and clinical advantages to addressing coronal curvature from the convex versus concave side of the curve. In this study, the authors aimed to broadly evaluate the clinical outcomes of addressing ASD with circumferential MIS (cMIS) techniques while accessing the lumbar coronal curvature from the concave side.

METHODS

A multi-institution, retrospective chart and radiographic review was performed for all ASD patients with at least a 10° curvature, as defined by the Scoliosis Research Society, who underwent cMIS correction. The data collected included convex versus concave access to the coronal curve, durable or sensory femoral nerve injury lasting longer than 6 weeks, vascular injury, visceral injury, and any additional major complication, with at least a 2-year follow-up. Neither health-related quality-of-life metrics nor spinopelvic parameters were included within the scope of this study.

RESULTS

A total of 152 patients with ASD treated with cMIS correction via lateral access were identified and analyzed. Of these, 126 (82.9%) were approached from the concave side and 26 (17.1%) were approached from the convex side. In the concave group, 1 (0.8%) motor and 4 (3.2%) sensory deficit cases remained at 6 weeks after the operation. No vascular, visceral, or catastrophic intraoperative injuries were encountered in the concave group. Of the 26 patients in the convex group, 2 (7.7%) experienced motor deficits lasting longer than 6 weeks and 5 (19.2%) had lower-extremity sensory deficits.

CONCLUSIONS

It has been reported that lateral access to the convex side is associated with similar clinical and radiographic outcomes with fewer complications when compared with access to the concave side. Advantages to approaching the lumbar spine from the concave side include using one incision to access multiple levels, breaking the operative table to assist with curvature correction, easier access to the L4-5 disc space, the ability to release the contracted side, and, often, avoidance of the need to access or traverse the thoracic cavity. This study illustrates the largest reported cohort of concave access for cMIS scoliosis correction; few postoperative sensory and motor deficits were found.

The minimally invasive interbody selection algorithm for spinal deformity

OBJECTIVE

Minimally invasive surgery (MIS) for spinal deformity uses interbody techniques for correction, indirect decompression, and arthrodesis. Selection criteria for choosing a particular interbody approach are lacking. The authors created the minimally invasive interbody selection algorithm (MIISA) to provide a framework for rational decision-making in MIS for deformity.

METHODS

A retrospective data set of circumferential MIS (cMIS) for adult spinal deformity (ASD) collected over a 5-year period was analyzed by level in the lumbar spine to identify surgeon preferences and evaluate segmental lordosis outcomes. These data were used to inform a Delphi session of minimally invasive deformity surgeons from which the algorithm was created. The algorithm leads to 1 of 4 interbody approaches: anterior lumbar interbody fusion (ALIF), anterior column release (ACR), lateral lumbar interbody fusion (LLIF), and transforaminal lumbar interbody fusion (TLIF). Preoperative and 2-year postoperative radiographic parameters and clinical outcomes were compared.

RESULTS

Eleven surgeons completed 100 cMISs for ASD with 338 interbody devices, with a minimum 2-year follow-up. The type of interbody approach used at each level from L1 to S1 was recorded. The MIISA was then created with substantial agreement. The surgeons generally preferred LLIF for L1-2 (91.7%), L2-3 (85.2%), and L3-4 (80.7%). ACR was most commonly performed at L3-4 (8.4%) and L2-3 (6.2%). At L4-5, LLIF (69.5%), TLIF (15.9%), and ALIF (9.8%) were most commonly utilized. TLIF and ALIF were the most selected approaches at L5-S1 (61.4% and 38.6%, respectively). Segmental lordosis at each level varied based on the approach, with greater increases reported using ALIF, especially at L4-5 (9.2°) and L5-S1 (5.3°). A substantial increase in lordosis was achieved with ACR at L2-3 (10.9°) and L3-4 (10.4°). Lateral interbody arthrodesis without the use of an ACR did not generally result in significant lordosis restoration. There were statistically significant improvements in lumbar lordosis (LL), pelvic incidence-LL mismatch, coronal Cobb angle, and Oswestry Disability Index at the 2-year follow-up.

CONCLUSIONS

The use of the MIISA provides consistent guidance for surgeons who plan to perform MIS for deformity. For L1-4, the surgeons preferred lateral approaches to TLIF and reserved ACR for patients who needed the greatest increase in segmental lordosis. For L4-5, the surgeons' order of preference was LLIF, TLIF, and ALIF, but TLIF failed to demonstrate any significant lordosis restoration. At L5-S1, the surgical team typically preferred an ALIF when segmental lordosis was desired and preferred a TLIF if preoperative segmental lordosis was adequate.

Complications After Adult Spinal Deformity Surgeries: All Are Not Created Equal

BACKGROUND

Data on timing of complications are important for accurate quality assessments. We sought to better define pre- and postdischarge complications occurring within 90 days of adult spinal deformity (ASD) surgery and quantify the effect of multiple complications on recovery.

METHODS

We performed a review of 1040 patients who underwent ASD surgery (age: 46 ± 23; body mass index: 25 ± 7, American Society of Anesthesiologists [ASA] score: 2.5 ± 0.6, levels: 10 ± 4, revision: 9%, 3-column osteotomy: 13%). We assessed pre- and postdischarge complications and risk factors for isolated versus multiple complications, as well as the impact of multiple complications.

RESULTS

The 90-day complication rate was 17.7%. 85 patients (8.2%) developed a predischarge complication, most commonly ileus (12%), and pulmonary embolism (PE; 7.1%). The most common causes of predischarge unplanned reoperation were neurologic injury (12.9%) and surgical site drainage (8.2%). Predictors of a predischarge complication included smoking (odds ratio [OR]: 2.2, P = .02), higher ASA (OR: 1.8, P = .008), hypertension (HTN; OR: 2.0, P = .004), and iliac fixation (OR: 4.3, P < .001). Ninety-nine patients (9.5%) developed a postdischarge complication, most commonly infection (34%), instrumentation failure (13.4%), and proximal junctional failure (10.4%). Predictors of postdischarge complications included chronic obstructive pulmonary disease (OR: 3.6, P < .0001), congestive heart failure (OR: 4.4, P = .016), HTN (OR: 2.3, P < .0001), and multiple rod construct (OR: 1.8, P = .02). Patients who developed multiple complications (9.3%) had a longer length of stay, and increased risk for readmission and unplanned reoperation.

CONCLUSIONS

Knowledge regarding timing of postoperative complications in relation to discharge may better inform quality improvement measures. PE and implant-related complications play a prominent role in perioperative complications and need for readmission, with several modifiable risk factors identified.

LEVEL OF EVIDENCE

Level 3.

CLINICAL RELEVANCE

Advances in surgical techniques and instrumentation have improved postoperative radiographic and clinical outcomes after ASD surgery. The rate of complications after complex ASD surgery remains high, both at early postoperative and long term follow-up. This study reviews complications within 90 days of surgery, with an assessment of patient and surgical risk factors. We found that modifiable risk factors for early complications after ASD surgery include COPD, and current smoking. The data presented in this study also provide surgeons with knowledge of the most common complications encountered after ASD surgery, to aid in preoperative patient discussion.

Artificial Intelligence-enabled, Real-time Intraoperative Ultrasound Imaging of Neural Structures Within the Psoas: Validation in a Porcine Spine Model

STUDY DESIGN

Experimental in-vivo animal study.

OBJECTIVE

The aim of this study was to evaluate an Artificial Intelligence (AI)-enabled ultrasound imaging system's ability to detect, segment, classify, and display neural and other structures during trans-psoas spine surgery.

SUMMARY OF BACKGROUND DATA

Current methodologies for intraoperatively localizing and visualizing neural structures within the psoas are limited and can impact the safety of lateral lumbar interbody fusion (LLIF). Ultrasound technology, enhanced with AI-derived neural detection algorithms, could prove useful for this task.

METHODS

The study was conducted using an in vivo porcine model (50 subjects). Image processing and machine learning algorithms were developed to detect neural and other anatomic structures within and adjacent to the psoas muscle while using an ultrasound imaging system during lateral lumbar spine surgery (SonoVision,™ Tissue Differentiation Intelligence, USA). The imaging system's ability to detect and classify the anatomic structures was assessed with subsequent tissue dissection. Dice coefficients were calculated to quantify the performance of the image segmentation.

RESULTS

The AI-trained ultrasound system detected, segmented, classified, and displayed nerve, psoas muscle, and vertebral body surface with high sensitivity and specificity. The mean Dice coefficient score for each tissue type was >80%, indicating that the detected region and ground truth were >80% similar to each other. The mean specificity of nerve detection was 92%; for bone and muscle, it was >95%. The accuracy of nerve detection was >95%.

CONCLUSION

This study demonstrates that a combination of AI-derived image processing and machine learning algorithms can be developed to enable real-time ultrasonic detection, segmentation, classification, and display of critical anatomic structures, including neural tissue, during spine surgery. AI-enhanced ultrasound imaging can provide a visual map of important anatomy in and adjacent to the psoas, thereby providing the surgeon with critical information intended to increase the safety of LLIF surgery.Level of Evidence: N/A.

Practical answers to frequently asked questions for shared decision-making in adult spinal deformity surgery

OBJECTIVE

The shared decision-making (SDM) process provides an opportunity to answer frequently asked questions (FAQs). The authors aimed to present a concise list of answers to FAQs to aid in SDM for adult spinal deformity (ASD) surgery.

METHODS

From a prospective, multicenter ASD database, patients enrolled between 2008 and 2016 who underwent fusions of 5 or more levels with a minimum 2-year follow-up were included. All deformity types were included to provide general applicability. The authors compiled a list of FAQs from patients undergoing ASD surgery and used a retrospective analysis to provide answers. All responses are reported as either the means or the proportions reaching the minimal clinically important difference at the 2-year follow-up interval.

RESULTS

Of 689 patients with ASD who were eligible for 2-year follow-up, 521 (76%) had health-related quality-of-life scores available at the time of that follow-up. The mean age at the initial surgery was 58.2 years, and 78% of patients were female. The majority (73%) underwent surgery with a posterior-only approach. The mean number of fused levels was 12.2. Revision surgery accounted for 48% of patients. The authors answered 12 FAQs as follows:1. Will my pain improve? Back and leg pain will both be reduced by approximately 50%.2. Will my activity level improve? Approximately 65% of patients feel improvement in their activity level.3. Will I feel better about myself? More than 70% of patients feel improvement in their appearance.4. Is there a chance I will get worse? 4.1% feel worse at 2 years postoperatively.5. What is the likelihood I will have a complication? 67.8% will have a major or minor complication, with 47.8% having a major complication.6. Will I need another surgery? 25.0% will have a reoperation within 2 years.7. Will I regret having surgery? 6.5% would not choose the same treatment.8. Will I get a blood transfusion? 73.7% require a blood transfusion.9. How long will I stay in the hospital? You need to stay 8.1 days on average.10. Will I have to go to the ICU? 76.0% will have to go to the ICU.11. Will I be able to return to work? More than 70% will be working at 1 year postoperatively.12. Will I be taller after surgery? You will be 1.1 cm taller on average.

CONCLUSIONS

The above list provides concise, practical answers to FAQs encountered in the SDM process while counseling patients for ASD surgery.

Breast cancer spinal metastases: Prognostic factors affecting survival after surgery. A retrospective study

Breast cancer spinal metastases (BCSM) are common and require proper treatment that leads to an improvement of the quality of life and contributes to the quod vitam prognosis. Surgical treatment is often required for intractable pain, spinal cord compression or spinal instability. The aim of this retrospective study is to identify which prognostic factors could affect postoperative overall survival in patients affected by BCSM. We report a retrospective cohort study of patients with BCSM, surgically treated from September 2009 to May 2018. Demographic and clinical data were collected. Kaplan-Meier method was used to estimate overall survival, and the log-rank test was used to compare survival curves. A total of 77 patients were studied. The median age at the time of surgery was 54 years. The median follow-up was 49 months. The 3-year and 5-year overall survival rates were 61% (95%CI: 47.5-72.1) and 43.3% (95%CI: 28.8-57.1). Metastatic bone disease (p = 0.0196), preoperative neurological impairment (p = 0.0029), Karnofsky status <70 (p = 0.0241) reduce survival. With multivariate analysis, the effect of Karnofsky score loses statistical significance. The presence of concurrent bone metastases and a preoperative neurological deficit are independent prognostic factors. Therapeutic choices are based on a multidisciplinary assessment that takes into consideration several factors, including an accurate study of prognostic factors.

Weekly Teriparatide Versus Bisphosphonate for Bone Union During 6 Months After Multi-Level Lumbar Interbody Fusion for Osteoporotic Patients: A Multicenter, Prospective, Randomized Study

STUDY DESIGN

Multicenter, prospective randomized study.

OBJECTIVE

Evaluate the impact of weekly teriparatide (WT) and bone contact (BC) status of grafted bone in patients recovering from multilevel lumbar interbody fusion (M-LIF).

SUMMARY OF BACKGROUND DATA

WT has been reported to significantly improve bone fusion following posterior or transforaminal interbody fusion in osteoporosis patients.

METHODS

Patients older than 50 years and osteoporotic were recruited. We defined the fusion of two or more consecutive intervertebral levels as M-LIF. All patients were instrumented with pedicle, iliac, or S-2 alar iliac screws after transplanting cages and autogenous bone between vertebral bodies. After surgical indication for M-LIF, the subjects were randomly allocated to receive either subcutaneous WT from 1 week to 6 months postoperatively (WT arm, N = 50) or a bisphosphonate (BP; BP arm, N = 54). Blinded radiological evaluations were performed using computed tomography (CT). Evaluation of bone fusion was performed at the intervertebral disc located at the bottom of the fixed range. The degree of bone fusion was calculated as a score from 2 to 6 points, with 2 defined as complete fusion. Bone fusion rate was also compared at 6 months postoperatively based on BC status of the grafted bone on CT immediately after surgery.

RESULTS

Mean bone fusion score at 6 months postoperatively was 3.9 points in the WT group and 4.2 points in the BP group. The bone fusion rate at 6 months postoperatively tended to be higher in the WT group (46.8% vs. 32.7% in the BP group). The 6-month postoperative fusion rate of immediately postoperative of BC+ patients was significantly higher than that of BC- patients (47.4% vs. 9.5%).

CONCLUSION

In M-LIF, there were no significant differences in bone fusion score between WT- and BP-treated patients. In contrast, BC status immediately postoperatively had a major impact on 6-month bone fusion.

LEVEL OF EVIDENCE

1.

Artificial Intelligence Models Predict Operative Versus Nonoperative Management of Patients with Adult Spinal Deformity with 86% Accuracy

OBJECTIVE

Patients with ASD show complex and highly variable disease. The decision to manage patients operatively is largely subjective and varies based on surgeon training and experience. We sought to develop models capable of accurately discriminating between patients receiving operative versus nonoperative treatment based only on baseline radiographic and clinical data at enrollment.

METHODS

This study was a retrospective analysis of a multicenter consecutive cohort of patients with ASD. A total of 1503 patients were included, divided in a 70:30 split for training and testing. Patients receiving operative treatment were defined as those undergoing surgery up to 1 year after their baseline visit. Potential predictors included available demographics, past medical history, patient-reported outcome measures, and premeasured radiographic parameters from anteroposterior and lateral films. In total, 321 potential predictors were included. Random forest, elastic net regression, logistic regression, and support vector machines (SVMs) with radial and linear kernels were trained.

RESULTS

Of patients in the training and testing sets, 69.0% (n = 727) and 69.1% (n = 311), respectively, received operative management. On evaluation with the testing dataset, performance for SVM linear (area under the curve =0.910), elastic net (0.913), and SVM radial (0.914) models was excellent, and the logistic regression (0.896) and random forest (0.830) models performed very well for predicting operative management of patients with ASD. The SVM linear model showed 86% accuracy.

CONCLUSIONS

This study developed models showing excellent discrimination (area under the curve >0.9) between patients receiving operative versus nonoperative management, based solely on baseline study enrollment values. Future investigations may evaluate the implementation of such models for decision support in the clinical setting.

Team Approach: Safety and Value in the Practice of Complex Adult Spinal Surgery

Surgical management of complex adult spinal deformities is of high risk, with a substantial risk of operative mortality. Current evidence shows that potential risk and morbidity resulting from surgery for complex spinal deformity may be minimized through risk-factor optimization. The multidisciplinary team care model includes neurosurgeons, orthopaedic surgeons, physiatrists, anesthesiologists, hospitalists, psychologists, physical therapists, specialized physician assistants, and nurses. The multidisciplinary care model mimics previously described integrated care pathways designed to offer a structured means of providing a comprehensive preoperative medical evaluation and evidence-based multimodal perioperative care. The role of each team member is illustrated in the case of a 66-year-old male patient with previous incomplete spinal cord injury, now presenting with Charcot spinal arthropathy and progressive vertebral-body destruction resulting in lumbar kyphosis.