Durability of Satisfactory Functional Outcomes Following Surgical Adult Spinal Deformity Correction: A 3-Year Survivorship Analysis

Factors Influencing Maintenance of Alignment and Functional Improvement Following Adult Spinal Deformity Surgery: A 3-Year Outcome Analysis

STUDY DESIGN

This was a retrospective review.

OBJECTIVE

To assess the factors contributing to durability of surgical results following adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND

Factors contributing to the long-term sustainability of ASD correction are currently undefined.

MATERIALS AND METHODS

Operative ASD patients with preoperatively (baseline) and 3-year postoperatively radiographic/health-related quality of life data were included. At 1 and 3 years postoperatively, a favorable outcome was defined as meeting at least three of four criteria: (1) no proximal junctional failure or mechanical failure with reoperation, (2) best clinical outcome (BCO) for Scoliosis Research Society (SRS) (≥4.5) or Oswestry Disability Index (ODI) (<15), (3) improving in at least one SRS-Schwab modifier, and (4) not worsening in any SRS-Schwab modifier. A robust surgical result was defined as having a favorable outcome at both 1 and 3 years. Predictors of robust outcomes were identified using multivariable regression analysis with conditional inference tree for continuous variables.

RESULTS

We included 157 ASD patients in this analysis. At 1 year postoperatively, 62 patients (39.5%) met the BCO definition for ODI and 33 (21.0%) met the BCO for SRS. At 3 years, 58 patients (36.9%) had BCO for ODI and 29 (18.5%) for SRS. Ninety-five patients (60.5%) were identified as having a favorable outcome at 1 year postoperatively. At 3 years, 85 patients (54.1%) had a favorable outcome. Seventy-eight patients (49.7%) met criteria for a durable surgical result. Multivariable adjusted analysis identified the following independent predictors of surgical durability: surgical invasiveness >65, being fused to S1/pelvis, baseline to 6-week pelvic incidence and lumbar lordosis difference >13.9°, and having a proportional Global Alignment and Proportion score at 6 weeks.

CONCLUSIONS

Nearly 50% of the ASD cohort demonstrated good surgical durability, with favorable radiographic alignment and functional status maintained up to 3 years. Surgical durability was more likely in patients whose reconstruction was fused to the pelvis and addressed lumbopelvic mismatch with adequate surgical invasiveness to achieve full alignment correction.

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

BACKGROUND CONTEXT

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

PURPOSE

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

STUDY DESIGN/SETTING

Secondary analysis of a prospective surgical registry.

PATIENT SAMPLE

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

OUTCOME MEASURES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Which frailty scales for patients with adult spinal deformity are feasible and adequate? A systematic review

BACKGROUND CONTEXT

Frailty as a concept is not yet fully understood, and is not the same as comorbidity. It is associated with an increased risk of adverse events and mortality after surgery, which makes its preoperative assessment significant. Despite its relevance, it still remains unclear which scales are appropriate for use in patients with spinal pathology.

PURPOSE

To evaluate the feasibility and measurement properties of frailty scales for spine patients, specifically with adult spinal deformity (ASD), and to propose adequate scales for primary triage to prevent surgery in too frail patients and for preoperative assessment to modify patients' condition and surgical plans.

STUDY DESIGN/SETTING

Systematic review.

METHODS

Systematic search was performed between 2010 and 2021 including terms relating to spinal disorders, frailty scales, and methodological quality. Characteristics of the studies and frailty scales and data describing relation to treatment outcomes were extracted. The risk of bias was determined with the QAREL score.

RESULTS

Of the 1993 references found, 88 original studies were included and 23 scales were identified. No prospective interventional study was found where the preoperative frailty assessment was implemented. Predictive value of scales for surgical outcomes varied, dependent on spinal disorders, type of surgeries, patients' age and frailty at baseline, and outcomes. Seventeen studies reported measurement properties of eight scales but these studies were not free of bias. In 30 ASD studies, ASD-Frailty Index (ASD-FI, n=14) and 11-item modified Frailty Index (mFI-11, n=11) were most frequently used. These scales were mainly studied in registry studies including young adult population, and carry a risk of sample bias and make their validity in elderly population unclear. ASD-FI covers multidisciplinary concepts of frailty with 40 items but its feasibility in clinical practice is questionable due to its length. The Risk Analysis Index, another multidisciplinary scale with 14 items, has been implemented for preoperative assessment in other surgical domains and was proven to be feasible and effective in interventional prospective studies. The FRAIL is a simple questionnaire with five items and its predictive value was confirmed in prospective cohort studies in which only elderly patients were included.

CONCLUSIONS

No adequate scale was identified in terms of methodological quality and feasibility for daily practice. Careful attention should be paid when choosing an adequate scale, which depends on the setting of interest (eg triage or preoperative work-up). We recommend to further study a simple and predictive scale such as FRAIL for primary triage and a comprehensive and feasible scale such as Risk Analysis Index for preoperative assessment for patients undergoing spine surgery, as their adequacy has been shown in other medical domains.

Adult Spinal Deformity Surgery and Frailty: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

Adult spinal deformity (ASD) can be a debilitating condition with a profound impact on patients' health-related quality of life (HRQoL). Many reports have suggested that the frailty status of a patient can have a significant impact on the outcome of the surgery. The present review aims to identify all pre-operative patient-specific frailty markers that are associated with postoperative outcomes following corrective surgery for ASD of the lumbar and thoracic spine.

METHODS

A systematic review of the literature was performed to identify findings regarding pre-operative markers of frailty and their association with postoperative outcomes in patients undergoing ASD surgery of the lumbar and thoracic spine. The search was performed in the following databases: PubMed, Embase, Cochrane and CINAHL.

RESULTS

An association between poorer performance on frailty scales and worse postoperative outcomes. Comorbidity indices were even more frequently employed with similar patterns of association between increased comorbidity burden and postoperative outcomes. Regarding the assessment of HRQoL, worse pre-operative ODI, SF-36, SRS-22 and NRS were shown to be predictors of post-operative complications, while ODI, SF-36 and SRS-22 were found to improve post-operatively.

CONCLUSIONS

The findings of this review highlight the true breadth of the concept of "frailty" in ASD surgical correction. These parameters, which include frailty scales and various comorbidity and HRQoL indices, highlight the importance of identifying these factors preoperatively to ensure appropriate patient selection while helping to limit poor postoperative outcomes.

Is Frailty Associated with Adverse Outcomes After Orthopaedic Surgery?: A Systematic Review and Assessment of Definitions

BACKGROUND

There is increasing evidence supporting the association between frailty and adverse outcomes after surgery. There is, however, no consensus on how frailty should be assessed and used to inform treatment. In this review, we aimed to synthesize the current literature on the use of frailty as a predictor of adverse outcomes following orthopaedic surgery by (1) identifying the frailty instruments used and (2) evaluating the strength of the association between frailty and adverse outcomes after orthopaedic surgery.

METHODS

A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, Scopus, and the Cochrane Central Register of Controlled Trials were searched to identify articles that reported on outcomes after orthopaedic surgery within frail populations. Only studies that defined frail patients using a frailty instrument were included. The methodological quality of studies was assessed using the Newcastle-Ottawa Scale (NOS). Study demographic information, frailty instrument information (e.g., number of items, domains included), and clinical outcome measures (including mortality, readmissions, and length of stay) were collected and reported.

RESULTS

The initial search yielded 630 articles. Of these, 177 articles underwent full-text review; 82 articles were ultimately included and analyzed. The modified frailty index (mFI) was the most commonly used frailty instrument (38% of the studies used the mFI-11 [11-item mFI], and 24% of the studies used the mFI-5 [5-item mFI]), although a large variety of instruments were used (24 different instruments identified). Total joint arthroplasty (22%), hip fracture management (17%), and adult spinal deformity management (15%) were the most frequently studied procedures. Complications (71%) and mortality (51%) were the most frequently reported outcomes; 17% of studies reported on a functional outcome.

CONCLUSIONS

There is no consensus on the best approach to defining frailty among orthopaedic surgery patients, although instruments based on the accumulation-of-deficits model (such as the mFI) were the most common. Frailty was highly associated with adverse outcomes, but the majority of the studies were retrospective and did not identify frailty prospectively in a prediction model. Although many outcomes were described (complications and mortality being the most common), there was a considerable amount of heterogeneity in measurement strategy and subsequent strength of association. Future investigations evaluating the association between frailty and orthopaedic surgical outcomes should focus on prospective study designs, long-term outcomes, and assessments of patient-reported outcomes and/or functional recovery scores.

CLINICAL RELEVANCE

Preoperatively identifying high-risk orthopaedic surgery patients through frailty instruments has the potential to improve patient outcomes. Frailty screenings can create opportunities for targeted intervention efforts and guide patient-provider decision-making.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The influence of sagittal spinopelvic alignment on patient discharge disposition following minimally invasive lumbar interbody fusion

Background

The aim of this study was to investigate the changes to spinopelvic sagittal alignment following minimally invasive (MIS) lumbar interbody fusion, and the influence of such changes on postoperative discharge disposition.

Methods

The Michigan Spine Surgery Improvement Collaborative was queried for all patients who underwent transforaminal lumbar interbody fusion (TLIF)or lateral lumbar interbody fusion (LLIF) procedures for degenerative spine disease. Several spinopelvic sagittal alignment parameters were measured, including sagittal vertical axis (SVA), lumbar lordosis, pelvic tilt, pelvic incidence, and pelvic incidence-lumbar lordosis mismatch. Primary outcome measure-discharge to a rehabilitation facility-was expressed as adjusted odds ratio (ORadj) following a multivariable logistical regression.

Results

Of the 83 patients in the study population, 11 (13.2%) were discharged to a rehabilitation facility. Preoperative SVA was equivalent. Postoperative SVA increased to 8.0 cm in the discharge-to-rehabilitation division versus a decrease to 3.6 cm in the discharge-to-home division (P<0.001). The odds of discharge to a rehabilitation facility increased by 25% for every 1-cm increase in postoperative sagittal balance (OR_adj =1.27, P=0.014). The strongest predictor of discharge to rehabilitation was increasing decade of life (OR_adj =3.13, P=0.201).

Conclusions

Correction of sagittal balance is associated with greater odds of discharge to home. These findings, coupled with the recognized implications of admission to a rehabilitation facility, will emphasize the importance of spine surgeons accounting for SVA into their surgical planning of MIS lumbar interbody fusions.