Trends in national utilization of posterior lumbar fusion and 30-day reoperation and readmission rates from 2006–2016

Rate and risk factors for inpatient falls following single-level posterior lumbar fusion: A national registry study

Background

Posterior lumbar fusion (PLF) is frequently considered for various spinal pathologies. While many outcome metrics have been assessed, to our knowledge, there has yet to be literature specifically investigating inpatient falls (IPFs) and its risk factors.

Methods

Adult patients who underwent single-level PLF were abstracted from the 2010-Q1 2022 M161Ortho PearlDiver Database. Patients who had an IPF were determined based on administrative coding. Various patient variables were extracted and variables independently associated with IPFs were assessed with multivariate logistic regression. Incidence of secondary injuries and cost incurred related to the IPF were determined.

Results

Of the 342,890 patients who underwent PLF, IPF was identified for 4,379 (1.4%). Independent predictors of an IPF in decreasing odds ratio (OR) order were those with: active psychosis (OR=3.35), active delirium (OR=2.83), history of falling (OR=2.47), commercial insurance (OR=1.59 relative to Medicare), Medicaid insurance (OR=1.47 relative to Medicare), dementia (OR=1.17), older age (OR=1.12 per decade), alcohol use disorder (O=1.11), higher comorbidity (OR=1.08 per Elixhauser comorbidity index point) (p<.05 for each).Of patients with IPF, 44 (1.0%) sustained a head injury, and 42 (1.0%) sustained a fracture. On average, those with IPF incurred greater inpatient costs compared to patients who did not ($36,865 vs. $33,921, p<.001).

Conclusion

In this national sample of patients who underwent single-level PLF, postoperative IPFs were identified for 1.4% and were associated with defined patient variables. These findings have potential patient outcome, financial, and medicolegal implications and should help guide refinement of fall prevention programs.

Patterns in Decompression and Fusion Procedures for Patients With Lumbar Stenosis After Major Clinical Trial Results, 2016 to 2019

Importance

Use of lumbar fusion has increased substantially over the last 2 decades. For patients with lumbar stenosis and degenerative spondylolisthesis, 2 landmark prospective randomized clinical trials (RCTs) published in the New England Journal of Medicine in 2016 did not find clear evidence in favor of decompression with fusion over decompression alone in this population.

Objective

To assess the national use of decompression with fusion vs decompression alone for the surgical treatment of lumbar stenosis and degenerative spondylolisthesis from 2016 to 2019.

Design, Setting, and Participants

This retrospective cohort study included 121 745 hospitalized adult patients (aged ≥18 years) undergoing 1-level decompression alone or decompression with fusion for the management of lumbar stenosis and degenerative spondylolisthesis from January 1, 2016, to December 31, 2019. All data were obtained from the National Inpatient Sample (NIS). Analyses were conducted, reviewed, or updated on June 9, 2023.

Main Outcome and Measure

The primary outcome of this study was the use of decompression with fusion vs decompression alone. For the secondary outcome, multivariable logistic regression analysis was used to evaluate factors associated with the decision to perform decompression with fusion vs decompression alone.

Results

Among 121 745 eligible hospitalized patients (mean age, 65.2 years [95% CI, 65.0-65.4 years]; 96 645 of 117 640 [82.2%] non-Hispanic White) with lumbar stenosis and degenerative spondylolisthesis, 21 230 (17.4%) underwent decompression alone, and 100 515 (82.6%) underwent decompression with fusion. The proportion of patients undergoing decompression alone decreased from 2016 (7625 of 23 405 [32.6%]) to 2019 (3560 of 37 215 [9.6%]), whereas the proportion of patients undergoing decompression with fusion increased over the same period (from 15 780 of 23 405 [67.4%] in 2016 to 33 655 of 37 215 [90.4%] in 2019). In univariable analysis, patients undergoing decompression alone differed significantly from those undergoing decompression with fusion with regard to age (mean, 68.6 years [95% CI, 68.2-68.9 years] vs 64.5 years [95% CI, 64.3-64.7 years]; P < .001), insurance status (eg, Medicare: 13 725 of 21 205 [64.7%] vs 53 320 of 100 420 [53.1%]; P < .001), All Patient Refined Diagnosis Related Group risk of death (eg, minor risk: 16 900 [79.6%] vs 83 730 [83.3%]; P < .001), and hospital region of the country (eg, South: 7030 [33.1%] vs 38 905 [38.7%]; Midwest: 4470 [21.1%] vs 23 360 [23.2%]; P < .001 for both comparisons). In multivariable logistic regression analysis, older age (adjusted odds ratio [AOR], 0.96 per year; 95% CI, 0.95-0.96 per year), year after 2016 (AOR, 1.76 per year; 95% CI, 1.69-1.85 per year), self-pay insurance status (AOR, 0.59; 95% CI, 0.36-0.95), medium hospital size (AOR, 0.77; 95% CI, 0.67-0.89), large hospital size (AOR, 0.76; 95% CI, 0.67-0.86), and highest median income quartile by patient residence zip code (AOR, 0.79; 95% CI, 0.70-0.89) were associated with lower odds of undergoing decompression with fusion. Conversely, hospital region in the Midwest (AOR, 1.34; 95% CI, 1.14-1.57) or South (AOR, 1.32; 95% CI, 1.14-1.54) was associated with higher odds of undergoing decompression with fusion. Decompression with fusion vs decompression alone was associated with longer length of stay (mean, 2.96 days [95% CI, 2.92-3.01 days] vs 2.55 days [95% CI, 2.49-2.62 days]; P < .001), higher total admission costs (mean, $30 288 [95% CI, $29 386-$31 189] vs $16 190 [95% CI, $15 189-$17 191]; P < .001), and higher total admission charges (mean, $121 892 [95% CI, $119 566-$124 219] vs $82 197 [95% CI, $79 745-$84 648]; P < .001).

Conclusions and Relevance

In this cohort study, despite 2 prospective RCTs that demonstrated the noninferiority of decompression alone compared with decompression with fusion, use of decompression with fusion relative to decompression alone increased from 2016 to 2019. A variety of patient- and hospital-level factors were associated with surgical procedure choice. These results suggest the findings of 2 major RCTs have not yet produced changes in surgical practice patterns and deserve renewed focus.

The 5-Factor Modified Frailty Index Score Predicts Return to the Operating Room for Patients Undergoing Posterior Spinal Fusion for Traumatic Spine Injury

OBJECTIVE

Within the trauma spine surgery literature, the effect of patient frailty on postoperative outcomes for posterior spinal fusion (PSF) remains clear. In this study, the authors quantified the influence of the 5-factor modified frailty index (mFI-5) score on hospital length of stay, diagnosis of a postoperative infection, 30-day readmission, and 90-day return to operating room (OR).

METHODS

The authors retrospectively reviewed the records of all patients with traumatic spine injury undergoing PSF by a single surgeon at our institution from 2016 to 2021. Data were extracted using manual chart review and the mFI-5 score was calculated using data on comorbidities. Bivariate (Mann-Whitney U test and Fisher exact test) and multivariate regressions (linear and logistic) revealed whether there was an independent relationship between patient frailty and postoperative outcomes.

RESULTS

The patient cohort included 263 patients (52.00 ± 19.04), 67 (25.5) were classified as frail, defined as having an mFI-5 score ≥2. Patients who were classified as frail were significantly more likely to have diabetes (odds ratio = 21.53; P < 0.001) and active cancer (odds ratio = 10.03; P = 0.004). Patients with mFI-5 scores ≥2 were also significantly older (P < 0.001) and had higher body mass index (BMI) (P = 0.007). Patients with mFI-5 scores >2 were more likely to return to the OR (odds ratio = 2.43; P = 0.037) on bivariate analysis. When controlling for demographics and clinical characteristics, mFI-5 score independently predicted return to OR (odds ratio = 1.294; P = 0.041).

CONCLUSIONS

Patient frailty independently predicted a return to OR in patients undergoing PSF for traumatic spine injury. Future studies can investigate methods for patient risk optimization to reduce morbidity and mortality.

The role of spinal surgery in the treatment of low back pain

Low back pain (LBP) is common and a leading cause of disability and lost productivity worldwide. Acute LBP is frequently self-resolving, but recurrence is common, and a significant proportion of patients will develop chronic pain. This transition is perpetuated by anatomical, biological, psychological and social factors. Chronic LBP should be managed with a holistic biopsychosocial approach of generally non-surgical measures. Spinal surgery has a role in alleviating radicular pain and disability resulting from neural compression, or where back pain relates to cancer, infection, or gross instability. Spinal surgery for all other forms of back pain is unsupported by clinical data, and the broader evidence base for spinal surgery in the management of LBP is poor and suggests it is ineffective. Emerging areas of interest include selection of a minority of patients who may benefit from surgery based on spinal sagittal alignment and/or nuclear medicine scans, but an evidence base is absent. Spinal surgery for back pain has increased substantially over recent decades, and disproportionately among privately insured patients, thus the contribution of industry and third-party payers to this increase, and their involvement in published research, requires careful consideration.

Minimally Invasive Surgical Decompression without Fusion for the Treatment of Lumbar Synovial Cysts: Feasibility and Long-Term Outcomes

BACKGROUND

Lumbar synovial cysts (LSCs) can cause painful radiculopathy and sensory and/or motor deficits. Historically, first-line surgical treatment has been decompression with fusion. Recently, minimally invasive laminectomy without fusion has shown equal or superior results to traditional decompression and fusion methods.

OBJECTIVE

This study investigates the long-term efficacy of minimally invasive laminectomy without fusion in the treatment of LSC as it relates to the rate of subsequent fusion surgery.

METHODS

A retrospective review was performed over a 10-year period of patients undergoing minimally invasive laminectomy for symptomatic LSCs. The primary end point was the rate of revision surgery requiring fusion.

RESULTS

Eighty-five patients with symptomatic LSCs underwent minimally invasive laminectomy alone January 2010-August 2020 at our institution. The most common location was L4-5 (72%). Preoperative imaging identified spondylolisthesis (grade 1) in 43 patients (57%), none of which was unstable on available dynamic radiographs. Average procedure duration was 93 minutes, with 78% of patients discharged home on the same day of surgery. Over 46 months of mean follow-up, 17 patients (20%) required 19 revision operations. Of those operations, 16 were spinal fusions (17.6%). Median time to fusion surgery was 36 months. There were no identifiable risk factors on multivariate regression analysis that predicted the need for fusion.

CONCLUSIONS

Minimally invasive laminectomy is an effective first-line treatment for symptomatic LSCs and avoids the need for fusion in most treated patients. Of our patients, 18% required a fusion over 46 months, suggesting that further studies are required to guide patient selection.

Surgical Site Infection in the Intensive Care Setting After Posterior Spinal Fusion: A Case Series Highlighting the Microbial Profile, Risk Factors, and the Importance of Comorbid Disease Burden

BACKGROUND

Most posterior spinal fusion (PSF) patients do not require admission to an intensive care unit (ICU), and those who do may represent an underinvestigated, high-risk subpopulation.

OBJECTIVE

To identify the microbial profile of and risk factors for surgical site infection (SSI) in PSF patients admitted to the ICU postoperatively.

METHODS

We examined 3965 consecutive PSF patients treated at our institution between 2000 and 2015 and collected demographic, clinical, and procedural data. Comorbid disease burden was quantified using the Charlson Comorbidity Index (CCI). We performed multivariable logistic regression to identify risk factors for SSI, readmission, and reoperation.

RESULTS

Anemia, more levels fused, cervical surgery, and cerebrospinal fluid leak were positively associated with ICU admission, and minimally invasive surgery was negatively associated. The median time to infection was equivalent for ICU patients and non-ICU patients, and microbial culture results were similar between groups. Higher CCI and undergoing a staged procedure were associated with readmission, reoperation, and SSI. When stratified by CCI into quintiles, SSI rates show a strong linear correlation with CCI ( P = .0171, R = 0.941), with a 3-fold higher odds of SSI in the highest risk group than the lowest (odds ratio = 3.15 [1.19, 8.07], P = .032).

CONCLUSION

Procedural characteristics drive the decision to admit to the ICU postoperatively. Patients admitted to the ICU have higher rates of SSI but no difference in the timing of or microorganisms that lead to those infections. Comorbid disease burden drives SSI in this population, with a 3-fold greater odds of SSI for high-risk patients than low-risk patients.

Using Predictive Modeling and Supervised Machine Learning to Identify Patients at Risk for Venous Thromboembolism Following Posterior Lumbar Fusion

STUDY DESIGN

Retrospective review.

OBJECTIVE

To use predictive modeling and machine learning to identify patients at risk for venous thromboembolism (VTE) following posterior lumbar fusion (PLF) for degenerative spinal pathology.

METHODS

Patients undergoing single-level PLF in the inpatient setting were identified in the National Surgical Quality Improvement Program database. Our outcome measure of VTE included all patients who experienced a pulmonary embolism and/or deep venous thrombosis within 30-days of surgery. Two different methodologies were used to identify VTE risk: 1) a novel predictive model derived from multivariable logistic regression of significant risk factors, and 2) a tree-based extreme gradient boosting (XGBoost) algorithm using preoperative variables. The methods were compared against legacy risk-stratification measures: ASA and Charlson Comorbidity Index (CCI) using area-under-the-curve (AUC) statistic.

RESULTS

13, 500 patients who underwent single-level PLF met the study criteria. Of these, 0.95% had a VTE within 30-days of surgery. The 5 clinical variables found to be significant in the multivariable predictive model were: age > 65, obesity grade II or above, coronary artery disease, functional status, and prolonged operative time. The predictive model exhibited an AUC of 0.716, which was significantly higher than the AUCs of ASA and CCI (all, P < 0.001), and comparable to that of the XGBoost algorithm (P > 0.05).

CONCLUSION

Predictive analytics and machine learning can be leveraged to aid in identification of patients at risk of VTE following PLF. Surgeons and perioperative teams may find these tools useful to augment clinical decision making risk stratification tool.