Adult Spinal Deformity: National Trends in the Presentation, Treatment, and Perioperative Outcomes From 2003 to 2010

Risk Factors for Sacroiliac Joint Fusion after Instrumented Spinal Fusion

Study DesignRetrospective Cohort Study.ObjectiveTo identify risk factors for sacroiliac (SI) joint fusion after instrumented spinal fusion.MethodsPatients were identified from the PearlDiver BiscayneBay database. Patients who underwent 1 level (CPT: 22840), 3-6 vertebral segment (22842), and 7+ vertebral segment spinal fusions (22843 and 22844) were identified. Patients were separated based on whether they received an SI joint fusion (27280 and 27279) after their spinal fusion. A univariate analysis and multivariate logistic regression was performed to evaluate the associations between patient factors and incidence of SI joint fusion.Results549,625 patients who underwent posterior spinal fusions were identified, 6068 of whom underwent subsequent SI joint fusion (1.1%). Factors associated with future SI joint fusion included female gender, patients with obesity, fibromyalgia, diabetes, tobacco use, increased construct length, and prior SI joint injection. Prior SI joint injection had the highest odds ratio (OR: 8.70; 95% CI: 8.25-9.16; P < 0.001), followed by 7+ vertebral segment (OR: 2.17; 95% CI: 2.03-2.33; P < 0.001) and 3-6 vertebral segment fusion (OR: 1.49; 95% CI: 1.42-1.57; P < 0.001).ConclusionsThe highest predictor of requiring subsequent SI joint fusion is a prior SI joint injection. We also found that longer fusion constructs are associated with increased risk for future SI joint fusion.

The combined effect of nutritional status and body mass index on 90-day adverse events following long-segments fusion for adult spinal deformity: a propensity score-matched analysis

OBJECTIVE

The aim of this study was to investigate the individual and combined effects of PNI (prognostic nutritional index) and BMI (body mass index) on 90-day adverse events (AEs) following adult spinal deformity (ASD) surgery.

METHODS

A retrospective analysis was conducted on prospectively collected data from patients who underwent open long-segment fusion surgery for ASD. Patients were stratified into four groups based on BMI and PNI: low BMI with low PNI (LBLP), high BMI with low PNI (HBLP), low BMI with high PNI (LBHP), and high BMI with high PNI (HBHP). The primary outcome was the incidence of postoperative AEs within 90 days of ASD surgery.

RESULTS

The LBLP group had a significantly higher risk of overall AEs (58.7% vs. 33.3%, p = 0.004) and infectious complications (20.6% vs. 7.9%, p = 0.042) compared to the LBHP group. The HBHP group exhibited a higher rate of major AEs (28.1% vs. 12.3%, p = 0.036) and infectious complications (15.6% vs. 3.5%, p = 0.026) within 90 days postoperatively than the LBHP group. Multivariate logistic regression analysis identified male, higher American Society of Anesthesiologists class, increased intraoperative blood loss, and HBHP status (compared to LBHP) as independent predictors of 90-day major AEs.

CONCLUSION

In patients with low PNI, those with low BMI had a significantly higher risk of overall adverse events and infectious complications. Conversely, among patients with high PNI, those with high BMI were more prone to major adverse events and infectious complications within 90 days postoperatively.

Association between paraspinal muscle quality and surgery for adjacent segment disease

Background

Adjacent segment disease (ASD) is one of the most common complications after spinal fusion. There are several risk factors for ASD, but recently the quality of the paraspinal musculature has been implicated as a potential risk factor. The purpose of this study is to examine the association between paraspinal muscle degeneration and risk of surgery for ASD.

Methods

We conducted a retrospective review of spinal fusion patients at our institution from 2009 to 2022 who underwent subsequent surgery for ASD. Inclusion criteria included patients aged 18 and older at time of index operation. Control cohort included patients who did not undergo subsequent surgery for adjacent segment disease with a minimum one year follow up. Patients were matched based on age, gender, and BMI. We measured paraspinal fat percentage and circumferential surface area (CSA) at L3 and at the proximal end of their future construct. Paraspinal fat percentage and CSA were measured using ImageJ (National Institutes of Health, Bethesda, Maryland, USA). Student T-test was used to evaluate for statistically significant differences with p-value ≤ .05.

Results

A total of 154 patients were reviewed with 77 patients in each cohort. The average age and BMI in the control group was 61.3 and 30.0 versus 61.2 and 29.6 in patients who underwent subsequent surgery. Overall, patients who underwent surgery for adjacent segment disease had 24% higher paraspinal fat percentage at L3 (13.8 ± 7.7% vs. 11.1 ± 6.5%, p-value = .02) and 22% higher paraspinal fat percentage at the top end of their construct (16.0 ± 9.0% vs. 13.1 ± 7.1%, p-value = .03).

Conclusions

Our study found that patients who undergo surgery for adjacent segment disease have 24% higher fat percentage in their paraspinal musculature at L3 and 22% higher fat percentage at the proximal end of their fusion construct.

Long-term mechanical failure in well aligned adult spinal deformity patients

BACKGROUND CONTEXT

Mechanical complications (MC) are frequently linked to suboptimal postoperative alignment and represent a primary driver of revision surgery in the context of adult spinal deformity (ASD). However, it's worth noting that even among those deemed "well aligned," the risk of experiencing MCs persists, hinting at the potential influence of factors beyond alignment.

PURPOSE

The aim was to assess the incidence of MCs among well-aligned patients and delving into the relevant risk factors and surgical outcomes that come into play within this specific subgroup.

STUDY DESIGN/SETTING

A retrospective analysis was conducted using data from a prospective multicenter database dedicated to ASD.

PATIENT SAMPLE

The study focused on patients aged 55 years or older, who had a minimum follow-up period of 2 years, and exhibited a Global Alignment and Proportion (GAP) score of 2 points or less (excluding age) within 6 weeks of their index surgery.

OUTCOME MEASURES

Mechanical complications such as rod fractures, pseudarthrosis, or junctional kyphosis or failure.

METHODS

Patients who developed mechanical complications were identified. Comparative analyses were performed, encompassing both continuous and categorical variables. Furthermore, binary logistic regression tests were employed to pinpoint risk factors, and ROC curves were used to determine the optimal threshold values for these variables.

RESULTS

A total of 83 patients met the inclusion criteria for this study, with a mean age of 66 years. On average, they had 10 instrumented levels, and 77% of them had fusion extending to the pelvis. Additionally, 27% of the patients had undergone 3-column osteotomies (3-CO). Among them, 33 patients (40%) experienced at least 1 MC during an average follow-up period of 4 years, which included 14 cases of proximal junctional kyphosis (PJK) and 20 cases of nonunion or rod breakage. 15 patients (18%) required revision surgery specifically for MC. In univariable analyses, patients who developed MC were characterized by higher body weight, poorer baseline general health (as indicated by worse SF-36 scores), and less favorable preoperative coronal and sagittal alignment. They also had longer hospital stays, a greater number of instrumented levels, and achieved less favorable postoperative coronal and sagittal alignment. Interestingly, factors such as 3-column osteotomies, postoperative bracing, and the addition of an anterior approach did not significantly alter the risk of MC in well-aligned ASD patients. Binary regression models revealed that independent risk factors for MC included the residual coronal lumbosacral curve, the number of instrumented levels, and relative spinopelvic alignment (RSA). ROC curves identified an optimal threshold of a residual lumbosacral curve of ≤4° and RSA of ≤3°. Moreover, the rate of MCs showed a stepwise increase within the GAP-Proportioned group, with rates of 31% for GAP=0, 54% for GAP=1, and 75% for GAP=2, with RSA emerging as the most influential parameter. Lastly, patients with MC exhibited poorer functional and radiological outcomes at their last follow-up assessment.

CONCLUSIONS

The rate of MCs remains elevated in sagittally "well-aligned" ASD patients that can be attributed to suboptimal residual sagittal and coronal malalignment, which in turn leads to poorer functional outcomes. This study reaffirms the multifaceted nature of MCs and underscores the significance of achieving impeccable postoperative alignment, particularly in the presence of additional risk factors such as extensive surgical correction, a high lever arm (involving instrumented vertebrae), excessive body weight, and frailty (as indicated by SF-36 scores).

Combined anterior-posterior versus posterior only approach for surgical management of adult spinal deformity: a systematic review and meta-analysis of comparative studies

PURPOSE

The purpose of this systematic review and meta-analysis was to examine the clinical outcomes and complication rates for fusion procedures of adult spinal deformity (ASD) performed via an anterior-posterior approach as compared to a posterior-only approach to guide surgical decision-making. Numerous surgical techniques exist for operative management of ASD; however, no systematic review and meta-analysis exists comparing combined anterior-posterior approaches to posterior-only approach, despite significant interest in the current literature.

METHODS

Four databases were used to collect articles from database inception until September 9th, 2023. Inclusion criteria was articles that examined both anterior-posterior or posterior only surgical approach, adult patients, comparative studies, and articles in English.

RESULTS

Seven comparative articles met the inclusion criteria. Included patients had a frequency weighted (FW) mean age of 60.2 ± 5.1 years and a FW mean follow-up of 40.4 ± 12.5 months. Qualitative data did not favor either group in terms of length of stay, radiographic outcomes, or functional outcomes. There was a total of 306 complications in the Anterior-Posterior group with a complication rate per patient of 1.0 ± 0.9 complications whereas there was a total of 380 complications in the Posterior Only group with a complication rate per patient of 1.0 ± 1.2 complications. Meta-analysis of specific complications found no significant difference in revision rate, dural tear rate, neurological complication rate, infection rate, or pseudoarthrosis rate.

CONCLUSION

Surgical management for ASD may provide comparable results in terms of surgical parameters, radiographic outcomes, functional outcomes, and complication rates, irrespective of surgical approach.

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

STUDY DESIGN

Retrospective cohort study.

PURPOSE

The impact of neuromuscular disorders such as multiple sclerosis (MS) on outcomes following long segment fusion is underreported. This study evaluates the impact of MS on two-year (2Y) postoperative complications and revisions following ≥ 4-level fusion for adult spinal deformity (ASD).

METHODS

Patients undergoing ≥ 4-level fusion for ASD were identified from a statewide database. Patients with a baseline diagnosis of MS were also identified. Patients with infectious/traumatic/neoplastic indications were excluded. Subjects were 1:1 propensity score-matched (MS to no-MS) based on age, sex and race and compared for rates of 2Y postoperative complications and reoperations. Logistic regression models were utilized to determine risk factors for adverse outcomes at 2Y.

RESULTS

86 patients were included overall (n = 43 per group). Age, sex, and race were comparable between groups (p > 0.05). MS patients incurred higher charges for their surgical visit ($125,906 vs. $84,006, p = 0.007) with similar LOS (8.1 vs. 5.3 days, p > 0.05). MS patients experienced comparable rates of overall medical complications (30.1% vs. 25.6%) and surgical complications (34.9% vs. 30.2%); p > 0.05. MS patients had similar rates of 2Y revisions (16.3% vs. 9.3%, p = 0.333). MS was not associated with medical, surgical, or overall complications or revisions at minimum 2Y follow-up.

CONCLUSION

Patients with MS experienced similar postoperative course compared to those without MS following ≥ 4-level fusion for ASD. This data supports the findings of multiple previously published case series' that long segment fusions for ASD can be performed relatively safely in patients with MS.

Alignment considerations in degenerative spinal conditions: A narrative review

Background

With an aging population, degenerative spinal diseases are contributing significantly to the healthcare's burden. Spinal alignment in the context of adult spinal deformities has become an important domain of research.

Methods

We conducted a narrative review of the latest considerations in spinal alignment within the context of degenerative spinal conditions, discussed current strategies for morphological assessment and finally identified potential areas for future research.

Results

This review reported that degenerative spinal conditions lead to a complex disruption of spinal alignment. It also highlighted the importance of spino-pelvic alignment with specific attention to compensatory mechanisms that occur in response to spinal deformities. Emerging technologies including Artificial Intelligence and epigenetics are showing promises in terms of patient care.

Conclusions

Understanding spinal alignment in degenerative conditions underscores the importance of dynamic and individualized assessments. Future research should integrate emerging technologies along with traditional clinical practices in order to optimize patient outcomes and minimize complications for patients suffering from degenerative spinal diseases.

Barbed sutures versus conventional sutures for wound closure in spine surgeries: a systematic review and meta-analysis

Suturing techniques for wound closure in spine surgeries play a critical role in patient outcomes, including wound healing, reintervention, and risk of complications. Barbed sutures, characterized by their self-anchoring properties, have emerged as a potential alternative to conventional sutures in various surgical disciplines. While previous studies have underscored their efficacy and safety in spine surgeries, no meta-analysis has been conducted. Therefore, we are undertaking this study. Following the PRISMA guidelines, we conducted a literature search on electronic databases to obtain the relevant studies until May 5, 2024. Our primary outcomes were operative time, wound closure time, and postoperative wound complications like seroma or hematoma formation and wound infection. The secondary outcomes were the length of hospital stay, reintervention rates, and costs. Data was pooled using a random effects model. We included seven eligible studies with a total of 8645 patients. Our meta-analysis showed that barbed sutures had shorter operative time and wound closure time compared to conventional sutures (MD -20.13 min, 95% CI [-28.47, -11.78], P < 0.001) and (MD -16.36 min, 95% CI [-20.9, -11.82], P < 0.001), respectively. Both suturing techniques showed comparable results in terms of overall postoperative wound complications (RR 0.83, 95% CI [0.60, 1.14], P = 0.25), postoperative infections (RR 0.59, 95% CI [0.33, 1.06], P = 0.08), length of hospital stay (MD -0.26 day, 95% CI [-0.75, 0.22], P = 0.28), rates of reintervention between the two groups (RR 0.99, 95% CI [0.48, 2.05], P = 0.98). Barbed sutures in spine surgeries are associated with significantly shortened wound closure and operative times. However, high-quality RCT's with long-term follow-up and cost-effectiveness assessment are required to support the evidence.

Adult cervical spine deformity: a state-of-the-art review

Adult cervical deformity is a structural malalignment of the cervical spine that may present with variety of significant symptomatology for patients. There are clear and substantial negative impacts of cervical spine deformity, including the increased burden of pain, limited mobility and functionality, and interference with patients' ability to work and perform everyday tasks. Primary cervical deformities develop as the result of a multitude of different etiologies, changing the normal mechanics and structure of the cervical region. In particular, degeneration of the cervical spine, inflammatory arthritides and neuromuscular changes are significant players in the development of disease. Additionally, cervical deformities, sometimes iatrogenically, may present secondary to malalignment or correction of the thoracic, lumbar or sacropelvic spine. Previously, classification systems were developed to help quantify disease burden and influence management of thoracic and lumbar spine deformities. Following up on these works and based on the relationship between the cervical and distal spine, Ames-ISSG developed a framework for a standardized tool for characterizing and quantifying cervical spine deformities. When surgical intervention is required to correct a cervical deformity, there are advantages and disadvantages to both anterior and posterior approaches. A stepwise approach may minimize the drawbacks of either an anterior or posterior approach alone, and patients should have a surgical plan tailored specifically to their cervical deformity based upon symptomatic and radiographic indications. This state-of-the-art review is based upon a comprehensive overview of literature seeking to highlight the normal cervical spine, etiologies of cervical deformity, current classification systems, and key surgical techniques.

Surgical and Clinical Outcomes Associated With the Use of Barbed Sutures and Self-Adhering Mesh System and Polymeric Glue for Wound Closure in Multilevel or Revision Spinal Surgery: A Matched Cohort Comparative Study With Conventional Wound Closure Procedure

OBJECTIVE

Multilevel or revisional posterior spinal surgery is prone to infection and delayed wound healing, related with the wound closure time and suture strength. Knotless barbed suture is an innovative self-locking, multianchor suture. This study aims to evaluate the safety and efficacy of the knotless barbed suture and self-adhering mesh with polymeric glue in multilevel or revisional posterior spinal surgery.

METHODS

This is a single-center retrospective matched cohort study. Patients were divided into 2 groups based on the wound closure method: barbed suture group with novel wound closure, and conventional suture group with conventional wound closure, 1:1 matched by the level of surgery and sex, resulting in 120 subjects each. Total operation time and wound closure time were measured intraoperatively, and perioperative clinical outcome parameters including postoperative wound complication were investigated for the first 3 months postoperatively. The distribution of continuous variables was assessed for normality by Shapiro-Wilk test, then parametric or nonparametric tests were applied accordingly (paired t-test or Wilcoxon signed-rank test).

RESULTS

Wound closure time was significantly shorter with the novel barbed suture than with conventional suture in all subgroups divided by the level of spinal surgery: 3-5, 6-9, ≥ 10 levels (p < 0.001). The 2 groups showed no significant differences in surgical complications (p = 1.000). Specially, total operation time and wound-closing time were significantly shorter in revisional subgroup.

CONCLUSION

Absorbable knotless barbed suture and self-adhering mesh with polymeric glue can shorten spinal wound closure time with noninferiority in complications for multilevel or revisional spinal surgery.

Revision surgery following long lumbopelvic constructs for adult spinal deformity: prospective experience from two dedicated databases

PURPOSE

Pan Lumbar Arthodesis (PLA) are often required for Adult Spinal Deformity (ASD) correction, reducing significantly the compensatory capacity in case of postoperative sagittal malalignment. Few papers have investigated outcomes and complications in this vulnerable subset of patients. The objective of this study was to assess revision surgery rate for PLA in ASD, its risk factors and impact on clinical outcomes.

METHODS

Retrospective multicenter review of prospective ASD data from 7 hospitals covering Europe and Asia. ASD patients included in two prospective databases having a posterior instrumentation spanning the whole lumbar region with more than 2-years of follow-up were reviewed. Demographic, surgical, radiographic parameters and Health-Related Quality of Life (HRQoL) scores were analyzed. Univariate and multivariate regression models analyzed risk factors for revision surgery as well as surgical outcomes. Patients with Early versus Late and PJK versus Non-PJK mechanical complications were also compared.

RESULTS

Out of 1359 ASD patients included in the database 589 (43%) had a PLA and 357 reached 2-years mark. They were analyzed and compared to non-PLA patients. Average age was 67 and 82% were females. 100 Patients (28.1%) needed 114 revision surgeries (75.4% for mechanical failures). Revised patients were more likely to have a nerve system disorder, higher BMI and worst immediate postoperative alignment (as measured by GAP Parameters). These risk factors were also associated with earlier mechanical complications and PJK. Deformity and HRQoL parameters were comparable at baseline. Non-revised patients had significantly better clinical outcomes at 2-years (SRS 22 scores, ODI, Back pain). Multivariate analysis could identify nerve system disorder (OR 4.8; CI 1.8-12.6; p = 0.001), postoperative sagittal alignment (GAP Score) and high BMI (OR 1.07; CI 1.01-1.13; p = 0.004) as independent risk factors for revisions.

CONCLUSIONS

Revision surgery due to mechanical failures is relatively common after PLA leading to worse clinical outcomes. Prevention strategies should focus on individualized restoration of sagittal alignment and better weight control to decrease stress on these rigid constructs in non-compliant spines. Nerve system disorders independently increase revision risk in PLA.

LEVEL OF EVIDENCE II

Prognosis.

Validation of Adult Spinal Deformity Surgical Outcome Prediction Tools in Adult Symptomatic Lumbar Scoliosis

STUDY DESIGN

A post hoc analysis.

OBJECTIVE

Advances in machine learning (ML) have led to tools offering individualized outcome predictions for adult spinal deformity (ASD). Our objective is to examine the properties of these ASD models in a cohort of adult symptomatic lumbar scoliosis (ASLS) patients.

SUMMARY OF BACKGROUND DATA

ML algorithms produce patient-specific probabilities of outcomes, including major complication (MC), reoperation (RO), and readmission (RA) in ASD. External validation of these models is needed.

METHODS

Thirty-nine predictive factors (12 demographic, 9 radiographic, 4 health-related quality of life, 14 surgical) were retrieved and entered into web-based prediction models for MC, unplanned RO, and hospital RA. Calculated probabilities were compared with actual event rates. Discrimination and calibration were analyzed using receiver operative characteristic area under the curve (where 0.5=chance, 1=perfect) and calibration curves (Brier scores, where 0.25=chance, 0=perfect). Ninety-five percent confidence intervals are reported.

RESULTS

A total of 169 of 187 (90%) surgical patients completed 2-year follow up. The observed rate of MCs was 41.4% with model predictions ranging from 13% to 68% (mean: 38.7%). RO was 20.7% with model predictions ranging from 9% to 54% (mean: 30.1%). Hospital RA was 17.2% with model predictions ranging from 13% to 50% (mean: 28.5%). Model classification for all three outcome measures was better than chance for all [area under the curve=MC 0.6 (0.5-0.7), RA 0.6 (0.5-0.7), RO 0.6 (0.5-0.7)]. Calibration was better than chance for all, though best for RA and RO (Brier Score=MC 0.22, RA 0.16, RO 0.17).

CONCLUSIONS

ASD prediction models for MC, RA, and RO performed better than chance in a cohort of adult lumbar scoliosis patients, though the homogeneity of ASLS affected calibration and accuracy. Optimization of models require samples with the breadth of outcomes (0%-100%), supporting the need for continued data collection as personalized prediction models may improve decision-making for the patient and surgeon alike.

Management of severe adult spinal deformity with circumferential minimally invasive surgical strategies without posterior column osteotomies: a 13-year experience

OBJECTIVE

To evaluate the mid- to long-term clinical outcomes of circumferential minimally invasive surgery (CMIS) without posterior column osteotomies for severe adult spine deformity (ASD) correction.

METHODS

All patients with a minimum of 2-year follow-up undergoing staged CMIS correction of ASD from January 2007 to July 2018 were identified. All included patients had fusion of 3 or more interbody levels that spanned the L5-S1 junction. Only patients with severe deformity, Coronal Cobb > 50° or at least one SRS-Schwab ++ sagittal modifier (SVA > 95 mm, or PI-LL > 20, or PT > 30) were included. All complications were noted.

RESULT

136 patients met inclusion criteria; mean age of patients was 63.6 years (21-85, SD 13.7). The mean follow-up was 82.8 months (24-159, SD 36.6). The mean number of levels fused was 7 (3-16, SD 3). A total of 40 (29.4%) major complications were noted at final follow-ups: 2 (1.4%) intra-operative, 12 (8.9%) peri-operative (≤ 6 weeks from index), 26 (19.1%) post-operative (> 6 weeks from index). There was a total of 53 (40.0%) minor complications. Seven (5.1%) patients who developed radiographic proximal junctional kyphosis. Three patients (2.2%) developed proximal junctional failure. There were 8 (5.9%) cases of pseudarthrosis. Five of these occurred in patients undergoing AxiaLIF. All patients experienced improvements in patient-perceived outcomes (VAS, TIS, ODI, and SRS-22) and radiographic parameters at last follow-up when compared to pre-op (p < 0.05).

CONCLUSION

Rates of complications with CMIS correction of severe ASD are lower than published rates of complications seen with open ASD correction. Specifically, the incidence of catastrophic complications is lower. Furthermore, CMIS is associated with significant improvements in clinical and functional outcomes, low rates of pseudarthrosis and proximal junctional kyphosis. Therefore, in the appropriately selected patient, CMIS may be an excellent alternative approach to addressing severe ASD.

Patient-reported outcome measure clustering after surgery for adult symptomatic lumbar scoliosis

OBJECTIVE

Adult symptomatic lumbar scoliosis (ASLS) is a widespread and debilitating subset of adult spinal deformity. Although many patients benefit from operative treatment, surgery entails substantial cost and risk for adverse events. Patient-reported outcome measures (PROMs) are patient-centered tools used to evaluate the appropriateness of surgery and to assist in the shared decision-making process. Framing realistic patient expectations should include the possible functional limitation to improvement inherent in surgical intervention, such as multilevel fusion to the sacrum. The authors' objective was to predict postoperative ASLS PROMs by using clustering analysis, generalized longitudinal regression models, percentile analysis, and clinical improvement analysis of preoperative health-related quality-of-life scores for use in surgical counseling.

METHODS

Operative results from the combined ASLS cohorts were examined. PROM score clustering after surgery investigated limits of surgical improvement. Patients were categorized by baseline disability (mild, moderate, moderate to severe, or severe) according to preoperative Scoliosis Research Society (SRS)-22 and Oswestry Disability Index (ODI) scores. Responder analysis for patients achieving improvement meeting the minimum clinically important difference (MCID) and substantial clinical benefit (SCB) standards was performed using both fixed-threshold and patient-specific values (MCID = 30% of remaining scale, SCB = 50%). Best (top 5%), worst (bottom 5%), and median scores were calculated across disability categories.

RESULTS

A total of 171/187 (91%) of patients with ASLS achieved 2-year follow-up. Patients rarely achieved a PROM ceiling for any measure, with 33%-43% of individuals clustering near 4.0 for SRS domains. Patients with severe baseline disability (< 2.0) SRS-pain and SRS-function scores were often left with moderate to severe disability (2.0-2.9), unlike patients with higher (≥ 3.0) initial PROM values. Patients with mild disability according to baseline SRS-function score were unlikely to improve. Crippling baseline ODI disability (> 60) commonly left patients with moderate disability (median ODI = 32). As baseline ODI disability increased, patients were more likely to achieve MCID and SCB (p < 0.001). Compared to fixed threshold values for MCID and SCB, patient-specific values were more sensitive to change for patients with minimal ODI baseline disability (p = 0.008) and less sensitive to change for patients with moderate to severe SRS subscore disability (p = 0.01).

CONCLUSIONS

These findings suggest that ASLS surgeries have a limit to possible improvement, probably due to both baseline disability and the effects of surgery. The most disabled patients often had moderate to severe disability (SRS < 3, ODI > 30) at 2 years, emphasizing the importance of patient counseling and expectation management.

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.

Supine Imaging Is a Superior Predictor of Long-Term Alignment Following Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To investigate correlations between preoperative supine imaging and postoperative alignment.

METHODS

A retrospective review was conducted of a single-institution database of patients with adult spinal deformity (ASD). Patients were stratified by fusion location in the lumbar or thoracic spine. Outcomes of interest were postoperative lumbar lordosis (LL) and thoracic kyphosis (TK). Sagittal alignment parameters were compared and correlation analyses were performed. Multilinear stepwise regression was conducted to identify independent predictors of postoperative LL or TK. Regression analyses were repeated within the lumbar and thoracic fusion cohorts.

RESULTS

A total of 99 patients were included (mean age 63.2 years, 83.1% female, mean body mass index 27.3 kg/m²). Scoliosis Research Society classification demonstrated moderate to severe sagittal and/or coronal deformity (pelvic tile modifier, 18.2% ++; sagittal vertical axis, 27.3% ++, pelvic incidence minus lumbar lordosis mismatch, 29.3% ++, SRS type, 29.3% N type curve and 68.7% L or D type curve). A total of 73 patients (73.7%) underwent lumbar fusion and 50 (50.5%) underwent thoracic fusion. Correlation analyses demonstrated a significant association between pre- and postoperative LL and TK. Multilinear regression demonstrated that LL supine and pelvic incidence were significant predictors of postoperative LL (r² = 0.568, P < .001). LL supine, TK supine, and age were significant predictors of postoperative TK (r² = 0.490, P < .001).

CONCLUSION

Preoperative supine films are superior to standing in predicting postoperative alignment at 1-year follow-up. Anticipation of undesired alignment changes through supine imaging may be useful in mitigating the risk of iatrogenic malalignment.

Growing Racial Disparities in the Utilization of Adult Spinal Deformity Surgery: An Analysis of Trends From 2004 to 2014

STUDY DESIGN

Retrospective.

OBJECTIVE

The purpose of this study was to assess trends in utilization rates of adult spinal deformity (ASD) surgery, as well as perioperative surgical metrics between Black and White patients undergoing operative treatment for ASD in the United States.

SUMMARY OF BACKGROUND DATA

Racial disparities in access to care, complications, and surgical selection have been shown to exist in the field of spine surgery. However, there is a paucity of data concerning racial disparities in the management of ASD patients.

METHODS

Adult patients undergoing ASD surgery from 2004 to 2014 were identified in the nationwide inpatient sample (NIS). Utilization rates, major complications rates, and length of stay (LOS) for Black patients and White patients were trended over time. Utilization rates were reported per 1,000,000 people and determined using annual census data among subpopulations stratified by race. All reported complication rates and prolonged hospital stay rates are adjusted for Elixhauser Comorbidity Index, income quartile by zip code, and insurance payer status.

RESULTS

From 2004 to 2014, ASD utilization for Black patients increased from 24.0 to 50.9 per 1,000,000 people, whereas ASD utilization for White patients increased from 29.9 to 73.1 per 1,000,000 people, indicating a significant increase in racial disparities in ASD utilization (P-trend < 0.001). There were no significant differences in complication rates or rates of prolonged hospital stay between Black and White patients across the time period studied (P > 0.05 for both).

CONCLUSION

Although Black and White patients undergoing ASD surgery do not differ significantly in terms of postoperative complications and length of hospital stay, there is a growing disparity in utilization of ASD surgery between White and Black patients from 2004 to 2014 in the United States. There is need for continued focus on identifying ways to reduce racial disparities in surgical selection and perioperative management in spine deformity surgery.Level of Evidence: 3.

Trends in Intraoperative Assessment of Spinal Alignment: A Survey of Spine Surgeons in the United States

STUDY DESIGN

Survey.

OBJECTIVES

To characterize national practices of and shortcomings surrounding intraoperative assessments of spinal alignment.

METHODS

Spine surgeons in the US were surveyed to analyze their experience with assessing spinal alignment intraoperatively.

RESULTS

108 US spine surgeons from 77 surgical centers with an average of 19.2 + 8.8 years of surgical experience completed the survey. To assess alignment intraoperatively, 84% (91/108) use C-arm or spot radiographs, 40% (43/108) use full-length radiographs, and 20% utilize the T-bar (22/108). 88% of respondents' surgical centers (93/106) possessed a navigation camera and 63% of respondents (68/108) report using surgical navigation for 40% of their deformity cases on average. Reported deterrents for using current technology to assess alignment were workflow interruption (54%, 58/108), expense (33%, 36/108), and added radiation exposure (26%, 28/108). 87% of respondents (82/94) reported a need for improvement in current capabilities of making intraoperative assessments of spinal alignment.

CONCLUSIONS

Corrective surgery for spinal deformity is a complex procedure that requires a high level of expertise to perform safely. The majority of surveyed surgeons primarily rely on radiographs for intraoperative assessments of alignment. Despite the majority of surveyed surgical practices possessing navigation cameras, they are utilized only for a minority of spinal deformity cases. With the majority of surveyed surgeons reporting a need for improvement in technology to assess spinal alignment intraoperatively, 3 of the top design considerations should include workflow interruption, expense, and radiation exposure.

Reaching the medicare allowable threshold in adult spinal deformity surgery: multicenter cost analysis comparing actual direct hospital costs versus what the government will pay

STUDY DESIGN

Retrospective multicenter cost analysis.

OBJECTIVE

To (1) determine if index episode of care (iEOC) costs of Adult Spinal Deformity (ASD) surgeries are below the Medicare Allowable (MA) threshold, and (2) identify variables that can predict iEOC cases that are below MA. Previous studies have suggested that actual direct hospital cost of Adult Spinal Deformity (ASD) surgery is higher than Medicare Allowable (MA) rates, which has become the benchmark reimbursement target for hospital accounting systems.

METHODS

From a prospective, multicenter ASD surgical database, patients undergoing long instrumented fusions (> 5 level) with cost data were identified. iEOC cost was calculated utilizing actual direct hospital cost. MA rates were calculated using hospital specific, year-appropriate CMS Inpatient Pricer Payment System. Recursive partitioning identified potentially modifiable variables that can predict iEOC cost < MA.

RESULTS

Administrative direct cost data from 210 patients were obtained from 4 of 11 centers. Ninety-five (45%) patients had iEOC cost < MA. There was significant variation across the four centers in both iEOC cost ($56,788-$78,878, p < 0.0001) and reimbursement ($40,623-$91,351, p < 0.0001) across deformity-specific DRGs (453,454,456,457). Academic centers were more likely to have iEOC costs < MA (67.2% vs 8.9%, p < 0.0001). Recursive partitioning (r² = 0.309) identified rhBMP-2 use of < 24 mg, sagittal plane deformity, a combined anterior/posterior approach, and an SF36-MCS < 39 as predictive for iEOC cost < MA. Performing an anterior/posterior approach reimburses between 14.7% and 121.1% more (2.2-fold) than posterior-only approach. This change in DRG allows iEOC cost to be more likely below the MA threshold.

CONCLUSION

There is significant institutional (private vs academic) variation in ASD reimbursement. BMP use, deformity type, approach, and baseline mental health impact ASD surgery cost being below Medicare reimbursement. ASD surgeries with anterior/posterior approaches are in DRGs that can potentially reimburse 2.2-fold the posterior-only surgery, making it more likely to fall below the MA threshold.

LEVEL OF EVIDENCE

III.

Quality metrics in adult spinal deformity surgery over the last decade: a combined analysis of the largest prospective multicenter data sets

OBJECTIVE

The reported rate of complications and cost of adult spinal deformity (ASD) surgery, associated with an exponential increase in the number of surgeries, cause alarm among healthcare payers and providers worldwide. The authors conjointly analyzed the largest prospective available ASD data sets to define trends in quality-of-care indicators (complications, reinterventions, and health-related quality of life [HRQOL] outcomes) since 2010.

METHODS

This is an observational prospective longitudinal cohort study. Patients underwent surgery between January 2010 and December 2016, with > 2 years of follow-up data. Demographic, surgical, radiological, and HRQOL (i.e., Oswestry Disability Index, SF-36, Scoliosis Research Society-22r) data obtained preoperatively and at 3, 6, 12, and 24 months after surgery were evaluated. Trends and changes in indicators were analyzed using local regression (i.e., locally estimated scatterplot smoothing [LOESS]) and adjusted odds ratio (OR).

RESULTS

Of the 2286 patients included in the 2 registries, 1520 underwent surgery between 2010 and 2016. A total of 1151 (75.7%) patients who were treated surgically at 23 centers in 5 countries met inclusion criteria. Patient recruitment increased progressively (2010-2011 vs 2015-2016: OR 1.64, p < 0.01), whereas baseline clinical characteristics (age, American Society of Anesthesiologists class, HRQOL scores, sagittal deformity) did not change. Since 2010 there has been a sustained reduction in major and minor postoperative complications observed at 90 days (major: OR 0.59; minor: OR 0.65; p < 0.01); at 1 year (major: OR 0.52; minor: 0.75; p < 0.01); and at 2 years of follow-up (major: OR 0.4; minor: 0.80; p < 0.01) as well as in the 2-year reintervention rate (OR 0.41, p < 0.01). Simultaneously, there has been a slight improvement in the correction of sagittal deformity (i.e., pelvic incidence-lumbar lordosis mismatch: OR 1.11, p = 0.19) and a greater gain in quality of life (i.e., Oswestry Disability Index 26% vs 40%, p = 0.02; Scoliosis Research Society-22r, self-image domain OR 1.16, p = 0.13), and these are associated with a progressive reduction of surgical aggressiveness (number of fused segments: OR 0.81, p < 0.01; percent pelvic fixation: OR 0.66, p < 0.01; percent 3-column osteotomies: OR 0.63, p < 0.01).

CONCLUSIONS

The best available data show a robust global improvement in quality metrics in ASD surgery over the last decade. Surgical complications and reoperations have been reduced by half, while improvement in disability increased and correction rates were maintained, in patients with similar baseline characteristics.

Increasing Cost Efficiency in Adult Spinal Deformity Surgery: Identifying Predictors of Lower Total Costs

STUDY DESIGN

Retrospective study of a prospective multicenter database.

OBJECTIVE

The purpose of this study was to identify predictors of lower total surgery costs at 3 years for adult spinal deformity (ASD) patients.

SUMMARY OF BACKGROUND DATA

ASD surgery involves complex deformity correction.

METHODS

Inclusion criteria: surgical ASD (scoliosis ≥20°, sagittal vertical axis [SVA] ≥5 cm, pelvic tilt ≥25°, or thoracic kyphosis ≥60°) patients >18 years. Total costs for surgery were calculated using the PearlDiver database. Cost per quality-adjusted life year was assessed. A Conditional Variable Importance Table used nonreplacement sampling set of 20,000 Conditional Inference trees to identify top factors associated with lower cost surgery for low (LSVA), moderate (MSVA), and high (HSVA) SRS Schwab SVA grades.

RESULTS

Three hundred sixtee of 322 ASD patients met inclusion criteria. At 3-year follow up, the potential cost of ASD surgery ranged from $57,606.88 to $116,312.54. The average costs of surgery at 3 years was found to be $72,947.87, with no significant difference in costs between deformity groups (P > 0.05). There were 152 LSVA patients, 53 MSVA patients, and 111 HSVA patients. For all patients, the top predictors of lower costs were frailty scores <0.19, baseline (BL) SRS Activity >1.5, BL Oswestry Disability Index <50 (all P < 0.05). For LSVA patients, no history of osteoporosis, SRS Activity scores >1.5, age <64, were the top predictors of lower costs (all P < 0.05). Among MSVA patients, ASD invasiveness scores <94.16, no past history of cancer, and frailty scores <0.3 trended toward lower total costs (P = 0.071, P = 0.210). For HSVA, no history of smoking and body mass index <27.8 trended toward lower costs (both P = 0.060).

CONCLUSION

ASD surgery has the potential for improved cost efficiency, as costs ranged from $57,606.88 to $116,312.54. Predictors of lower costs included higher BL SRS activity, decreased frailty, and not having depression. Additionally, predictors of lower costs were identified for different BL deformity profiles, allowing for the optimization of cost efficiency for all patients.Level of Evidence: 3.

COVID-19 Significantly Impacted Hospital Length of Stay and Discharge Patterns for Adult Spinal Deformity Patients

STUDY DESIGN

Retrospective review.

OBJECTIVE

The primary aim was to compare length of stay (LOS) and discharge disposition of adult spinal deformity (ASD) patients undergoing surgery before and during the pandemic. Secondary aims were to compare the rates of 30-day complications, reoperations, readmissions, and unplanned emergency department (ED) visits.

SUMMARY OF BACKGROUND DATA

ASD patients often require extended LOS and non-routine discharge. Given resource limitations during the Coronavirus Disease 2019 (COVID-19) pandemic and caution regarding hospital stays, surgeons modified standard postoperative protocols to minimize patient exposure.

METHODS

We identified all patients who underwent elective thoracolumbar ASD surgery with more than or equal to five levels fusion at a tertiary care center during two distinct time intervals: July to December 2019 (Pre-COVID, N = 60) and July to December 2020 (During-COVID, N = 57). Outcome measures included LOS and discharge disposition (home vs. non-home), as well as 30-day major complications, reoperations, readmissions, and ED visits. Regression analyses controlled for demographic and surgical factors.

RESULTS

Patients who underwent ASD surgery during the pandemic were younger (61 vs. 67 yrs) and had longer fusion constructs (nine vs. eight levels) compared with before the pandemic (P < 0.05 for both). On bivariate analysis, patients undergoing surgery during the pandemic had shorter LOS (6 vs. 9 days) and were more likely to be discharged home (70% vs. 28%) (P < 0.05 for both). After controlling for age and levels fused on multivariable regression, patients who had surgery during the pandemic had shorter LOS (IRR = 0.83, P = 0.015) and greater odds of home discharge (odds ratios [OR] = 7.2, P < 0.001). Notably, there were no differences in major complications, reoperations, readmissions, or ED visits between the two groups.

CONCLUSION

During the COVID-19 pandemic, LOS for patients undergoing thoracolumbar ASD surgery decreased, and more patients were discharged home without adversely affecting complication or readmission rates. Lessons learned during the pandemic may help improve resource utilization without negatively influencing short-term outcomes.Level of Evidence: 3.

National trends in lumbar spine decompression and fusion surgery in Finland, 1997-2018

Background and purpose - During recent years, spine surgery techniques have advanced, the population has become older, and multiple high-quality randomized controlled trials that support surgical treatment for degenerative spinal stenosis and spondylolisthesis have been published. We assess the incidence and trends in spine fusion and decompression surgery in Finland between 1997 and 2018.Patients and methods - We used nationwide data from the Finnish nationwide National Hospital Discharge Register. The study population covered all patients aged 20 years or over in Finland (5.5 million inhabitants) during a 22-year period from 1997 through 2018. All patients who underwent spinal decompression were included. Patients with both decompression and fusion codes were analyzed as fusions.Results - 76,673 lumbar spine decompressions and fusions were performed during the study period. The incidence of lumbar spine decompressions increased from 33 (95% CI 23-45) per 100,000 person-years in 1997 to 77 (CI 61-95) per 100,000 person-years in 2018. The incidence of lumbar spine fusions increased from 9 (CI 5-17) per 100,000 person-years in 1997 to 30 (CI 21-43) per 100,000 person-years in 2018. The increase in incidence of lumbar spinal fusions was highest among women aged over 75 years, with a 4-fold increase.Interpretation - The incidence of lumbar spine fusions and decompressions increased between 1997 and 2018 in Finland. These findings may be the result of the emergence of advanced surgical techniques but may also be the result of an aging population and increased evidence supporting the surgical treatment of various spinal pathologies.

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

INTRODUCTION

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Understanding the Trends and Variability in Procedures Performed During Orthopedic Spine Surgery Fellowship Training: An Analysis of ACGME Case Log Data

OBJECTIVE

To understand trends and variability of procedures performed by orthopedic spine surgery fellows during training.

DESIGN

Cross-sectional survey.

SETTING

Accreditation Council on Graduate Medical Education (ACGME) case logs.

PARTICIPANTS

Fellows enrolled in ACGME-accredited "Orthopaedic Surgery of the Spine" fellowships from 2010 to 2015.

RESULTS

The 2010 to 2015 ACGME fellowship case logs for "Orthopaedic Surgery of the Spine" were retrieved. Spine cases in case logs are grouped into the following categories: (1) Excision, (2) Osteotomy, (3) Fracture and/or Dislocation, (4) Decompression, (5) Anterior fusion/arthrodesis, (6) Posterior fusion, (7) Deformity surgery, (8) Exploration, (9) Instrumentation, and (10) other/uncategorized. The total number of spine cases logged by each fellow increased from 821 in 2010 to 1134 in 2015 (38.2% increase). The greatest increases were noted from fracture/dislocation cases (77.9%), followed by posterior fusions (62.2%), anterior fusions (43.6%), decompressions (36.3%), and instrumentation (29.5%). The average number of deformity cases decreased from 23 in 2010 to 19 in 2016 (18.6% decrease). The average number of adult-only cases increased from 770 in 2010 to 1100 in 2015 (42.8% increase), whereas the average number of pediatric-only cases declined from 51 in 2010 to 35 in 2015 (32.1% decrease). Based on case logs from 2015, the greatest variation in case volume between the 10th centile and 90th centile of fellows was noted for deformity cases, followed by decompressions and posterior fusions.

CONCLUSIONS

Even though there has been a 38% increase in the overall number of spine cases performed by fellows during training, a large amount of variation in type of case exposure exists between fellowships. The findings of our study call for the establishment of minimal case volumes and/or uniformity of training spectrums across the nation to ensure appropriate surgical care is made accessible to all patients.

The relationship of global sagittal malalignment to fatty infiltration in the aging spine

PURPOSE

To investigate associations between muscle size, fat infiltration (FI), and global sagittal alignment in patients with adult spinal deformity (ASD).

METHODS

Retrospective cohort study was conducted on a single-institution database of ASD patients with preoperative radiographs and CTs. Following multiplanar reconstructions of CTs, images in the plane of each vertebra were generated. The posterior vertebral musculature (PVM) was contoured on axial images at three vertebral levels (T2, T10, L3). FI was calculated by comparing Hounsfield units within muscles to the normative values of fat. Correlation analyses were conducted between demographics, alignment, and muscle characteristics.

RESULTS

107 patients underwent preoperative spine CT (58yo, 79%F, BMI 27 kg/m²). Muscle data were available for 49 pts at T2, 39 pts at T10, and 81 pts at L3. Mean FI was T2 = 33% ± 18, T10 = 28% ± 19, L3_Erector = 39% ± 19, and L3_Psoas = 19% ± 9. FI correlated across levels (T2 vs. T10 r = 0.698; T10 vs L3_Erector r = 0.506; L3_Erector vs Psoas r = 0.419) and with demographics; older pts had greater fat percentages (r = 0.31-0.45) and BMIs (r = 0.24-0.51). Increased FI at T2, T10, and L3 was associated with increased pelvic retroversion (PT: r = 0.25-0.43), global deformity (TPA: r = 0.27-0.45), and anterior malalignment (SVA: r = 0.23-0.41). The degree of FI in the PVM increased with the severity of SRS-Schwab PT and SVA modifiers.

CONCLUSION

In ASD patients, global sagittal malalignment is related to FI of the PVM throughout the lumbar and thoracic spine, as identified through CT. Future research should investigate how FI relates to ASD pathogenesis.

Strategies for spinal surgery reimbursement: bundling in the working-age population

Introduction

Bundled payments for spine surgery, which is known for having high overall cost with wide variation, have been previously studied in older adults. However, there has been limited work examining bundled payments in working-age patients. We sought to identify the variation in the cost of spine surgery among working age adults in a large, national insurance claims database.

Methods

We queried the TRICARE claims database for all patients, aged 18–64, undergoing cervical and non-cervical spinal fusion surgery between 2012 and 2014. We calculated the case mix adjusted, price standardized payments for all aspects of care during the 60-, 90-, and 180-day periods post operation. Variation was assessed by stratifying Hospital Referral Regions into quintiles.

Results

After adjusting for case mix, there was significant variation in the cost of both cervical ($10,538.23, 60% of first quintile) and non-cervical ($20,155.59, 74%). Relative variation in total cost decreased from 60- to 180-days (63 to 55% and 76 to 69%). Index hospitalization was the primary driver of costs and variation for both cervical (1st-to-5th quintile range: $11,033–$19,960) and non-cervical ($18,565–$36,844) followed by readmissions for cervical ($0–$11,521) and non-cervical ($0–$13,932). Even at the highest quintile, post-acute care remained the lowest contribution to overall cost ($2070 & $2984).

Conclusions

There is wide variation in the cost of spine surgery across the United States for working age adults, driven largely by index procedure and readmissions costs. Our findings suggest that implementing episodes longer than the current 90-day standard would do little to better control cost variation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06112-0.

A Simpler, Modified Frailty Index Weighted by Complication Occurrence Correlates to Pain and Disability for Adult Spinal Deformity Patients

BACKGROUND

The Miller et al adult spinal deformity frailty index (ASD-FI) correlates with complication risk; however, its development was not rooted in clinical outcomes, and the 40 factors needed for its calculation limit the index's clinical utility. The present study aimed to develop a simplified, weighted frailty index for ASD patients METHODS: This study is a retrospective review of a single-center database. Component ASD-FI parameters contributing to overall ASD-FI score were assessed via Pearson correlation. Top significant, clinically relevant factors were regressed against ASD-FI score to generate the modified ASD-FI (mASD-FI). Component mASD-FI factors were regressed against incidence of medical complications, and factor weights were calculated from regression of these coefficients. Total mASD-FI score ranged from 0 to 21, and was calculated by summing weights of expressed parameters. Linear regression and published ASD-FI cutoffs generated corresponding mASD-FI frailty cutoffs: not frail (NF, <7), frail (7-12), severely frail (SF, >12). Analysis of variance assessed the relationship between frailty category and validated baseline measures of pain and disability at baseline.

RESULTS

The study included 50 ASD patients. Eight factors were included in the mASD-FI. Overall mean mASD-FI score was 5.7 ± 5.2. Combined, factors comprising the mASD-FI showed a trend of predicting the incidence of medical complications (Nagelkerke R ² = 0.558; Cox & Snell R ² = 0.399; P = .065). Breakdown by frailty category is NF (70%), frail (12%), and SF (18%). Increasing frailty category was associated with significant impairments in measures of pain and disability: Oswestry Disability Index (NF: 23.4; frail: 45.0; SF: 49.3; P < .001), SRS-22r (NF: 3.5; frail: 2.6; SF: 2.4; P = .001), Pain Catastrophizing Scale (NF: 41.9; frail: 32.4; SF: 27.6; P < .001), and NRS Leg Pain (NF: 2.3; frail: 7.2; SF: 5.6; P = .001).

CONCLUSIONS

This study modifies an existing ASD frailty index and proposes a weighted, shorter mASD-FI. The mASD-FI relies less on patient-reported variables, and it weights component factors by their contribution to adverse outcomes. Because increasing mASD-FI score is associated with inferior clinical measures of pain and disability, the mASD-FI may serve as a valuable tool for preoperative risk assessment.

Adult spinal deformity surgery: the effect of surgical start time on patient outcomes and cost of care

PURPOSE

There are reports investigating the effect of surgical start time (SST) on outcomes, length of stay (LOS) and cost in various surgical disciplines. However, this has not been studied in spine deformity surgery to date. This study compares outcomes for patients undergoing spinal deformity surgery based on SST.

METHODS

Patients at a single academic institution from 2008 to 2016 undergoing elective spinal deformity surgery (defined as fusing ≥ 7 segments) were divided by SST before or after 2 PM. Co-primary outcomes were LOS and direct costs. Secondary outcomes included delayed extubation, ICU stay, complications, reoperation, non-home discharge, and readmission rates.

RESULTS

There were 373 surgeries starting before 2 PM and 79 after 2 PM. The cohorts had similar demographics including age, sex, comorbidity burden, and levels fused. The late SST cohort had shorter operation durations (p = 0.0007). Multivariable linear regression showed no differences in LOS (estimate 0.4 days, CI - 1.2 to 2.0, p = 0.64) or direct cost (estimate $3652, 95% CI - $1449 to $8755, p = 0.16). Multivariable logistic regression revealed the late SST cohort was more likely to have delayed extubation (OR 2.6, 95% CI 1.4-4.9, p = 0.004) and non-home discharge (OR 2.2, 95% CI 1.1-4.2, p = 0.03). All other secondary outcomes were non-significant.

CONCLUSION

Patients undergoing spinal deformity surgery before and after 2 PM have similar LOS and cost of care. However, the late SST cohort had increased likelihood of delayed extubation and non-home discharges, which increase cost in bundled payment models. These findings can be utilized in OR scheduling to optimize outcomes and minimize cost.

A cost utility analysis of treating different adult spinal deformity frailty states

The aim of this study was to investigate the cost utility of treating non-frail versus frail or severely frail adult spinal deformity (ASD) patients. 79 surgical ASD patients >18 years with available frailty and ODI data at baseline and 2-years post-surgery (2Y) were included. Utility data was calculated using the ODI converted to the SF-6D. QALYs utilized a 3% discount rate to account for decline to life expectancy (LE). Costs were calculated using the PearlDiver database. ICER was compared between non-operative (non-op.) and operative (op.) NF and F/SF patients at 2Y and LE. When compared to non-operative ASD, the ICER was $447,943.96 vs. $313,211.01 for NF and F/SF at 2Y, and $68,311.35 vs. $47,764.61 for NF and F/SF at LE. Frail and severely frail patients had lower cost per QALY compared to not frail patients at 2Y and life expectancy, and had lower ICER values when compared to a non-operative cohort of ASD patients. While these results support operative correction of frail and severely frail patients, it is important to note that these patients are often at worse baseline disability, which is closely related to frailty scores, and have more opportunity to improve postoperatively. Furthermore, there may be a threshold of frailty that is not operable due to the risk of severe complications that is not captured by this analysis. While future research should investigate economic outcomes at extended follow up times, these findings support the cost effectiveness of ASD surgery at all frailty states.

Trends in Posterior Cervical Fusion for Deformity in the United States from 2000 to 2017

BACKGROUND

Posterior cervical decompression and fusion (PCF) is a common treatment for cervical spondylotic myelopathy. Treatment paradigms are shifting from simple decompression and fusion to correcting cervical deformities.

OBJECTIVE

To identify trends in PCF with an emphasis on cervical deformity and surgical complexity.

METHODS

Adults who underwent PCF from 2000 to 2017 were retrospectively identified in the Premier Healthcare Database (PHD) using International Classification of Disease Codes (ICD) 9 and 10. Patients were dichotomized into those with or without deformity diagnosis. PCF complexity was defined by adjunct surgical codes, including anterior cervical fusion, extension to thoracic levels, and osteotomy. Patient characteristics, including demographics, functional comorbidity index (FCI), and hospital characteristics, were extracted and annual procedures were projected to the US population.

RESULTS

A total of 68 415 discharges for PCF were identified. Compound annual growth rate (CAGR) of PCF from 2000 to 2017 for nondeformity cases was 9.7% and 16.5% for deformity. The demographics with the greatest growth were deformity patients aged 65 to 74 yr (15.1%). The CAGR of anterior cervical fusion and extension to thoracic levels was higher for deformity patients compared to nondeformity patients, 13.6% versus 3.9% and 20.4% versus 16.6%, respectively.

CONCLUSION

Rates of PCF for deformity are increasing at a greater rate than nondeformity PCF. The most growth was seen among deformity patients aged 65 to 74 yr. Surgical complexity is also changing with increasing use of anterior cervical fusion and extension of PCF to include thoracic levels.

The effectiveness of tranexamic acid on operative and perioperative blood loss in long-segment spinal fusions: a consecutive series of 119 primary procedures

OBJECTIVE

The aim of this study was to determine if the use of tranexamic acid (TXA) in long-segment spinal fusion surgery can help reduce perioperative blood loss, transfusion requirements, and morbidity.

METHODS

In this retrospective single-center study, the authors included 119 consecutive patients who underwent thoracolumbar fusion spanning at least 4 spinal levels from October 2016 to February 2019. Blood loss, transfusion requirements, perioperative morbidity, and adverse thrombotic events were compared between a cohort receiving intravenous TXA and a control group that did not.

RESULTS

There was no significant difference in any measure of intraoperative blood loss (1514.3 vs 1209.1 mL, p = 0.29) or transfusion requirement volume between the TXA and control groups despite a higher number of pelvic fusion procedures in the TXA group (85.9% vs 62.5%, p = 0.003). Postoperative transfusion volume was significantly lower in TXA patients (954 vs 572 mL, p = 0.01). There was no difference in the incidence of thrombotic complications between the groups.

CONCLUSIONS

TXA appears to provide a protective effect against blood loss in long-segment spine fusion surgery specifically when pelvic dissection and fixation is performed. TXA also seems to decrease postoperative transfusion requirements without increasing the risk of adverse thrombotic events.

Risk Factors of Clostridium Difficile Infection After Spinal Surgery: National Health Insurance Database

The purpose of this study was to evaluate risk factors of Clostridium Difficile infection (CDI) after spinal surgery using the Health Insurance Review and Assessment Service (HIRA) data. The incidence of postoperative CDI was investigated using HIRA data from 2012 to 2016. Cases involving CDI that occurred within a 30-day postoperative period were identified. Risk factors, including age, sex, comorbidities, postoperative infection, spinal surgery procedure, type of antibiotic, and duration of antibiotic use, were evaluated. Duration of hospital stay, medical cost, and mortality were also evaluated. In total, 71,322 patients were included. Presumed cases of CDI were identified in 57 patients, with CDI rate of 0.54 per 10,000 patient days. Advanced age, staged operation, postoperative infection, and the use of multiple antibiotics were significant risk factors. First-generation cephalosporins were shown to be associated with a lower incidence of CDI. CDI was also associated with longer hospital stays and increased medical cost, and it was an independent risk factor for increased mortality. Extra attention should be paid to patients at high risk for the development of postoperative CDI, and unnecessary use of multiple antibiotics should be avoided. Level of Evidence: Level III, retrospective cohort study.

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.

The Effects of Preoperative Steroid Therapy on Perioperative Morbidity and Mortality After Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVES

To identify the effects of preoperative steroid therapy on 30-day perioperative complications after adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND DATA

Chronic steroid therapy has demonstrated therapeutic effects in the treatment of various medical conditions but is also known to be associated with surgical complications. There remains a gap in the literature regarding the impact of chronic steroid therapy in predisposing patients to perioperative complications after elective surgery for ASD.

METHODS

We performed a retrospective analysis of data from the 2008-2015 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Patients were divided into two groups based on preoperative steroid therapy. Differences in baseline patient characteristics, comorbidities, and operative variables were assessed. Univariate analysis was performed to compare the incidence of perioperative complications. Multivariate stepwise logistic regression models were then used to adjust for baseline patient and operative variables in order to identify perioperative complications that were associated with preoperative steroid therapy.

RESULTS

We identified 7,936 patients who underwent surgery for ASD, of which 418 (5.3%) were on preoperative steroid therapy. Preoperative steroid therapy was an independent risk factor for four perioperative complications, including mortality (odds ratio [OR] 2.42, 95% confidence interval [CI] 1.30, 4.51; p = .005), wound dehiscence (OR 3.12, 95% CI 1.45, 6.70; p = .004), deep vein thrombosis (DVT) (OR 2.10, 95% CI 1.24, 3.55; p = .006), and blood transfusion (OR 1.34, 95% CI 1.08, 1.66; p < .007).

CONCLUSIONS

Patients on preoperative steroid therapy are at increased risk of 30-day mortality, wound dehiscence, DVT, and blood transfusion after surgery for ASD. An interdisciplinary approach to the perioperative management of steroid regimens is critical.

LEVEL OF EVIDENCE

Level III.

The Current State of Minimally Invasive Approaches to Adult Spinal Deformity

PURPOSE OF REVIEW

Minimally invasive approaches to adult spinal deformity (ASD) surgery have seen a large increase in popularity over the last decade, largely because these techniques are viewed as a potential improvement to the lengthy recovery and high complication rates observed after traditional open surgery for this pathology. The purpose of this review is to present a summary of the latest minimally invasive techniques used in adult spinal deformity surgery, examine whether MIS surgery can accomplish the goals of ASD surgery, and investigate whether MIS surgery is safer than traditional approaches.

RECENT FINDINGS

While minimally invasive approaches have been able to achieve similar patient-reported outcomes as open approaches, they are associated with their own unique complications. Furthermore, they are limited in their ability to correct severe sagittal imbalance. Emerging techniques, such as anterior column realignment and mini-open posterior column osteotomy, have been developed to address these limitations. The minimally invasive spinal deformity surgery algorithm (MISDEF) can help guide surgeons on which approaches may be appropriate for a particular case. To maximize the benefits of a minimally invasive approach without compromising the goals of ASD surgery, surgeons must be selective in choosing which cases are amenable to an MIS approach. Leading experts continue to develop algorithms to guide surgical decision-making. As we learn to better define our indications, understand treatment goals, and refine our techniques, MIS approaches will likely play an even larger role in a comprehensive ASD treatment strategy.

Long-term clinical and radiographic outcomes and patient satisfaction after adult spinal deformity correction

Background and Aims:

Adult spinal deformity surgery has increased with the aging population and modern surgical approaches, although it has high complication and reoperation rates. The permanence of radiographic correction, mechanical complications, predictive factors for poor patient-reported outcomes, and patient satisfaction were analyzed.

Material and Methods:

A total of 79 adult patients were retrospectively analyzed at baseline and 1–9 years after adult spinal deformity correction between 2007 and 2016. Patient-reported outcomes (Oswestry Disability Index, visual analog scale, and Scoliosis Research Society–30 scores), changes in radiographic alignment, indications for reoperation, predictors of poor outcomes according to the Oswestry Disability Index and Scoliosis Research Society–30 scores, and patient satisfaction with management were studied.

Results:

Oswestry Disability Index and visual analog scale scores (p = 0.001), radiographic correction of thoracic kyphosis, lumbar lordosis, and pelvic retroversion (p ⩽ 0.001) and sagittal vertical axis (p = 0.043) were significantly better at 4–5 years of follow-up than at baseline. The risk for the first reoperation owing to mechanical failure of instrumentation or bone was highest within the first year, at 13.9% (95% confidence interval = 8.0%–23.7%), and 29.8% (95% confidence interval = 19.4%–43.9%) at the 5-year follow-up. Oswestry Disability Index and Scoliosis Research Society–30 total scores had a good correlation (r = −0.78; 95% CI = −0.86 to –0.68; p < 0.001). Satisfaction with management was correlated with patient-reported outcomes. Male sex and depression (p = 0.021 and 0.018, respectively) predicted poor outcomes according to the Oswestry Disability Index and/or Scoliosis Research Society–30 score.

Conclusion:

The achieved significant radiographic correction was maintained 5 years postoperatively. Despite reoperations, patient satisfaction and clinical outcomes were good. Depression and male sex predicted poor clinical outcomes.