The Incidence of Double Crush Syndrome in Surgically Treated Patients

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

Cervical radiculopathy and peripheral entrapment neuropathies often have overlapping symptoms that are difficult to distinguish on physical examination. Small-scale studies have attempted to report the incidence of this phenomenon, often called double crush syndrome (DCS), with varying results. The present study aims to determine the incidence of concomitant cervical radiculopathy and peripheral nerve compression and to determine if the DCS hypothesis, which states that compression of a nerve at one site leaves it more susceptible to compression at another, is valid.

METHODS

The PearlDiver database was queried from 2010 to 2020. The incidence of peripheral neuropathy in cervical radiculopathy was assessed. Propensity score matching was used to determine if patients with cervical radiculopathy were more likely to have peripheral nerve compression compared to controls, and vice versa, to test the DCS hypothesis.

RESULTS

The database contains records of 90,772 632 patients. The incidence of carpal tunnel syndrome (CTS) or peripheral ulnar nerve compression (PUnC) in cervical radiculopathy was 9.98% and 3.15%, respectively. The incidence of both carpal tunnel syndrome and PUnC in cervical radiculopathy was 1.84%. Patients with cervical radiculopathy were more likely than matched controls to have both CTS (P < .001) and PUnC (P < .001). Patients with CTS (P < .001) and with PUnC (P < .001) were more likely to have cervical radiculopathy than the control cohort.

CONCLUSIONS

The incidence of DCS is reported. Patients with cervical radiculopathy are more likely than matched controls to have peripheral nerve compression, and vice versa, in support of the DCS hypothesis.

The Evolution of Risk Assessment in Spine Surgery: A Narrative Review

BACKGROUND

Risk assessment is critically important in elective and high-risk interventions, particularly spine surgery. This narrative review describes the evolution of risk assessment from the earliest instruments focused on general surgical risk stratification, to more accurate and spine-specific risk calculators that quantified risk, to the current era of big data.

METHODS

The PubMed and SCOPUS databases were queried on October 11, 2023 using search terms to identify risk assessment tools (RATs) in spine surgery. A total of 108 manuscripts were included after screening with full-text review using the following inclusion criteria: 1) study population of adult spine surgical patients, 2) studies describing validation and subsequent performance of preoperative RATs, and 3) studies published in English.

RESULTS

Early RATs provided stratified patients into broad categories and allowed for improved communication between physicians. Subsequent risk calculators attempted to quantify risk by estimating general outcomes such as mortality, but then evolved to estimate spine-specific surgical complications. The integration of novel concepts such as invasiveness, frailty, genetic biomarkers, and sarcopenia led to the development of more sophisticated predictive models that estimate the risk of spine-specific complications and long-term outcomes.

CONCLUSIONS

RATs have undergone a transformative shift from generalized risk stratification to quantitative predictive models. The next generation of tools will likely involve integration of radiographic and genetic biomarkers, machine learning, and artificial intelligence to improve the accuracy of these models and better inform patients, surgeons, and payers.

Top 25 Most Cited Articles on Intraoperative Computer Tomography-Guided Navigation in Spine Surgery

BACKGROUND

In recent years, the use of intraoperative computer tomography-guided (CT-guided) navigation has gained significant popularity among health care providers who perform minimally invasive spine surgery. This review aims to identify and analyze trends in the literature related to the widespread adoption of CT-guided navigation in spine surgery, emphasizing the shift from conventional fluoroscopy-based techniques to CT-guided navigation.

METHODS

Articles pertaining to this study were identified via a database review and were hierarchically organized based on the number of citations. An "advanced document search" was performed on September 28th, 2022, utilizing Boolean search operator terms. The 25 most referenced articles were combined into a primary list after sorting results in descending order based on the total number of citations.

RESULTS

The "Top 25" list for intraoperative CT-guided navigation in spine surgery cumulatively received a total of 2742 citations, with an average of 12 new citations annually. The number of citations ranged from 246 for the most cited article to 60 for the 25th most cited article. The most cited article was a paper by Siewerdsen et al., with 246 total citations, averaging 15 new citations per year.

CONCLUSIONS

Intraoperative CT-guided navigation is 1 of many technological advances that is used to increase surgical accuracy, and it has become an increasingly popular alternative to conventional fluoroscopy-based techniques. Given the increasing adoption of intraoperative CT-guided navigation in spine surgery, this review provides impactful evidence for its utility in spine surgery.

Top 25 Most-Cited Articles on Robotic-Assisted Lumbar Spine Surgery

BACKGROUND

Robot-guided lumbar spine surgery has evolved rapidly with evidence to support its utility and feasibility compared with conventional freehand and fluoroscopy-based techniques. The objective of this study was to assess trends among the top 25 most-cited articles pertaining to robotic-guided lumbar spine surgery.

METHODS

An "advanced document search" using Boolean search operator terms was performed on 16 November 2022 through the Web of Science and SCOPUS citation databases to determine the top 25 most-referenced articles on robotic lumbar spine surgery. The articles were compiled into a directory and hierarchically organized based on the total number of citations.

RESULTS

Cumulatively, the "Top 25" list for robot-assisted navigation in lumbar spine surgery received 2240 citations, averaging 97.39 citations annually. The number of citations ranged from 221 to 40 for the 25 most-cited articles. The most-cited study, by Kantelhardt et al, received 221 citations, averaging 18 citations per year.

CONCLUSIONS

As utilization of robot-guided modalities in lumbar spine surgery increases, this review highlights the most impactful studies to support its efficacy and implementation. Practical considerations such as cost-effectiveness, however, need to be better defined through further longitudinal studies that evaluate patient-reported outcomes and cost-utility.

CLINICAL RELEVANCE

Through an overview of the top 25 most-cited articles, the present review highlights the rising prominence and technical efficacy of robotic-guided systems within lumbar spine surgery, with consideration to pragmatic limitations and need for additional data to facilitate cost-effective applications.

LEVEL OF EVIDENCE: 5

Cervical Disc Arthroplasty: Rationale, Designs, and Results of Randomized Controlled Trials

BACKGROUND

This review outlines clinical data and characteristics of current Food and Drug Administration (FDA)-approved implants in cervical disc replacement/cervical disc arthroplasty (CDR/CDA) to provide a centralized resource for spine surgeons.

METHODS

Randomized controlled trials (RCTs) on CDR/CDA were identified using a search of the PubMed, Web of Science, and Google Scholar databases. The initial search identified 69 studies. Duplicates were removed, and the following inclusion criteria were applied when determining eligibility of RCTs for the current review: (1) discussing CDR/CDA prosthesis and (2) published within between 2010 and 2020. Studies without clinical data or that were not RCTs were excluded. All articles were reviewed independently by 2 authors, with the involvement of an arbitrator to facilitate consensus on any discrepancies.

RESULTS

A total of 34 studies were included in the final review. Findings were synthesized into a comprehensive table describing key features and clinical results for each FDA-approved CDR/CDA implant and are overall suggestive of expanding indications and increasing utilization.

CONCLUSIONS

RCTs have provided substantial evidence to support CDR/CDA for treating single- and 2-level cervical degenerative disc disease in place of conventional anterior cervical discectomy and fusion.

CLINICAL RELEVANCE

This review provides a resource that consolidates relevant clinical data for current FDA-approved implants to help spine surgeons make an informed decision during preoperative planning.

LEVEL OF EVIDENCE: 5

Systematic Review and Meta-Analysis of the Effect of Osteoporosis on Fusion Rates and Complications Following Surgery for Degenerative Cervical Spine Pathology

BACKGROUND

As the elderly population grows, the increasing prevalence of osteoporosis presents a unique challenge for surgeons. Decreased bone strength and quality are associated with hardware failure and impaired bone healing, which may increase the rate of revision surgery and the development of complications. The purpose of this review is to determine the impact of osteoporosis on postoperative outcomes for patients with cervical degenerative disease or deformity.

METHODS

A systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Medical Subject Headings terms involving spine surgery for cervical degenerative disease and osteoporosis were performed. This review focused on radiographic outcomes, as well as surgical and medical complications.

RESULTS

There were 16 studies included in the degenerative group and 9 in the deformity group. Across degenerative studies, lower bone mineral density was associated with increased rates of cage subsidence in osteoporotic patients undergoing operative treatment for cervical degenerative disease. Most studies reported varied results on the relationship between osteoporosis and other outcomes such as revision and readmission rates, costs, and perioperative complications. Our meta-analysis suggests that osteoporotic patients carry a greater risk of reduced fusion rates at 6 months and 1 year postoperatively. With respect to cervical deformity correction, although individual complication rates were unchanged with osteoporosis, the collective risk of incurring any complication may be increased in patients with poor bone stock.

CONCLUSIONS

Overall, the literature suggests that outcomes for osteoporotic patients after cervical spine surgery are multifactorial. Osteoporosis seems to be a significant risk factor for developing cage subsidence and pseudarthrosis postoperatively, whereas reports on medical and hospital-related metrics were inconclusive. Our findings highlight the challenges of caring for osteoporotic patients and underline the need for adequately powered studies to understand how osteoporosis changes the risk index of patients undergoing cervical spine surgery.

CLINICAL RELEVANCE

In patients undergoing cervical spine surgery for degenerative disease, osteoporosis is a significant risk factor for long-term postoperative complications-notably cage subsidence and pseudarthrosis. Given the elective nature of these procedures, interdisciplinary collaboration between providers should be routinely implemented to enable medical optimization of patients prior to cervical spine surgery.

LEVEL OF EVIDENCE: 1

The Incidence of Vertebral Artery Injury in Cervical Spine Surgery

BACKGROUND

Previously reported estimates of vertebral artery injuries (VAIs) during cervical spine surgery relied on self-reported survey studies and retrospective cohorts, which may not be reflective of national averages. The largest study to date reports an incidence of 0.07%; however, significant variation exists between different cervical spine procedures. This study aimed to identify the incidence of VAIs in patients undergoing cervical spine procedures for degenerative pathologies.

METHODS

In this retrospective cohort study, a national insurance database was used to access data from the period 2010-2020 of patients who underwent anterior cervical discectomy and fusion, anterior corpectomy, posterior cervical fusion (C3-C7), or C1-C2 posterior fusion for degenerative pathologies. Patients who experienced a VAI were identified, and frequencies for the different procedures were compared.

RESULTS

This study included 224,326 patients, and overall incidence of VAIs across all procedures was 0.03%. The highest incidence of VAIs was estimated in C1-C2 posterior fusion (0.12%-1.10%). The number of patients with VAIs after anterior corpectomy, anterior cervical discectomy and fusion, and posterior fusion was 14 (0.06%), 43 (0.02%), and 26 (0.01%), respectively.

CONCLUSIONS

This is the largest study to date to our knowledge that provides frequencies of VAIs in patients undergoing cervical spine surgery in the United States. The overall incidence of 0.03% is lower than previously reported estimates, but significant variability exists between procedures, which is an important consideration when counseling patients about risks of surgery.

Post-Operative Complications Associated with Long-Term NSAID or Long-Term Opioid Use Prior to Lumbar Spinal Fusion Surgery

OBJECTIVE

Lower back pain (LBP) has been implicated as a significant cause of chronic pain in the United States, often requiring analgesic use. In this study, we investigate the trends in long-term preoperative NSAID (LTN) and Opioid (LTO) use in patients with low back pain in the United States, and the resultant postoperative complications following lumbar fusion.

METHODS

In this retrospective cohort study of patients with lumbar pathologies, multivariate population-based regression models were developed using the 2010-2017 National Readmission Database. Short-term complications (30-, 90-day) and long-term complications (180-, 300-day) were analyzed at readmission.

RESULTS

Of patients diagnosed with LBP (N = 1427,190) we found a rise in LTO users and a fall in LTN users following 2015. We identified 654,264 individuals who received a lumbar spine fusion, of which 22,975 were LTN users and 11,213 were LTO users. LTO users had significantly higher total inpatient charges (p-value<0.0001) and LOS (p-value<0.0001), while LTN users had lower rates of acute infection (OR: 0.993, 95% CI: 0.987-0.999, p = 0.017) and acute posthemorrhagic anemia (OR: 0.957, 95% CI: 0.935-0.979, p < 0.001) at primary admission. Readmission analysis showed that LTN use had significantly lower odds of readmission compared to LTO use at all time points (p < 0.01 for all). LTN use had significantly higher odds of hardware failure (OR: 1.134, 95% CI: 1.039-1.237, p = 0.005) within 300-days of receiving a lumbar fusion.

CONCLUSIONS

LTO users had significantly higher readmission rates compared to LTN. In addition, we found that LTN use was associated with significantly higher odds of hardware failure at long-term follow-up in patients receiving lumbar fusion surgery.

The Influence of Hospital Type, Insurance Type, and Patient Income on 30-Day Complication and Readmission Rates Following Lumbar Spine Fusion

BACKGROUND CONTEXT

Several studies have shown that factors such as insurance type and patient income are associated with different readmission rates following certain orthopaedic procedures. The literature, however, remains sparse with regard to these demographic characteristics and their associations to perioperative lumbar spine fusion outcomes.

PURPOSE

The purpose of this study was to assess the associations between hospital type, insurance type, and patient median income to both 30-day complication and readmission rates following lumbar spine fusion.

PATIENT SAMPLE

Patients who underwent primary lumbar spine fusion (n = 596,568) from 2010-2016 were queried from the National Readmissions Database (NRD).

OUTCOME MEASURES

Incidence of 30-day complication and readmission rates.

METHODS

All relevant diagnoses and procedures were identified using International Classification of Disease, 9th and 10th Edition (ICD-9, 10) codes. Hospital types were categorized as metropolitan non-teaching (n = 212,131), metropolitan teaching (n = 364,752), and rural (n = 19,685). Insurance types included: Medicare (n = 213,534), Medicaid (n = 78,520), private insurance (n = 196,648), and out-of-pocket (n = 45,025). Patient income was divided into the following quartiles: Q1 (n = 112,083), Q2 (n = 145,755), Q3 (n = 156,276), and Q4 (n = 147,289), wherein quartile 1 corresponded to lower income ranges and quartile 4 to higher ranges. Statistical analysis was conducted in R. Kruskal-Wallis tests with Dunn's pairwise comparisons were performed to analyze differences in 30-day readmission and complication rates in patients who underwent lumbar spine fusion. Complications analyzed included infection, wound injury, hematoma, neurological injury, thromboembolic event, and hardware failure.

RESULTS

30-day readmission was significantly higher in metropolitan teaching hospitals compared to metropolitan non-teaching hospitals and rural hospitals (P < .05). Patients from metropolitan teaching hospitals had significantly higher rates of infection (P < .001), wound injury (P < .001), hematoma (P = .018), and hardware failure (P < .002) compared to those treated at metropolitan non-teaching hospitals. Privately insured patients were significantly less likely to be readmitted at 30 days than those paying with Medicare or Medicaid (P < .01). Patients with private insurance also experienced significantly lower rates of hematoma formation than Medicare beneficiaries and out-of-pocket payers (P < .01), postoperative wound injury compared to Medicaid patients and out-of-pocket payers (P < .005), and infection compared to all other groups (P < .001). Patients in Quartile 4 experienced significantly greater rates of hematoma formation compared to those in Quartiles 1 and 2 and were more likely to experience a thromboembolic event compared to all other groups.

CONCLUSION

Patients undergoing lumbar spine fusion at metropolitan non-teaching hospitals and paying with private insurance had significantly lower 30-day readmission rates than their counterparts. Complications within 30 days following lumbar spine fusion were significantly higher in patients treated at metropolitan teaching hospitals and in Medicare and Medicaid beneficiaries. Aside from a few exceptions, however, patient income was generally not associated with differential complication rates.

Preoperative Epidural Steroid Injection Does Not Increase Infection Risk Following Posterior Cervical Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The purpose of this study was to characterize the infection risk of preoperative epidural steroid injection (ESI) in patients undergoing posterior cervical surgery.

SUMMARY OF BACKGROUND DATA

ESI is a helpful tool for alleviating pain and is often used as a diagnostic tool before cervical surgery. However, a recent small-scale study found that ESI before cervical fusion was associated with an increased risk of postoperative infection.

MATERIALS AND METHODS

Patients from 2010 to 2020 with cervical myelopathy, spondylosis, and radiculopathy who underwent posterior cervical procedure including laminectomy, laminoforaminotomy, fusion, or laminoplasty were queried from the PearlDiver database. Patients who underwent revision or fusion above C2 or who had a diagnosis of neoplasm, trauma, or preexisting infection were excluded. Patients were divided on whether they received an ESI within 30 days before the procedure and subsequently matched by age, sex, and preoperative comorbidities. The χ 2 analysis was used to calculate the risk of postoperative infection within 90 days. Logistic regression controlling for age, sex, Elixhauser Comorbidity Index, and operated levels was conducted within the unmatched population to assess infection risk for injected patients across procedure subgroups.

RESULTS

Overall, 299,417 patients were identified with 3897 having received a preoperative ESI and 295,520 who did not. Matching resulted in 975 in the injected group and 1929 in the control group. There was no significant difference in postoperative infection rate in those who received an ESI within 30 days preoperatively and those who did not (3.28% vs. 3.78%, odds ratio=0.86, 95% CI: 0.57-1.32, P =0.494). Logistic regression accounting for age, sex, Elixhauser Comorbidity Index, and levels operated demonstrated that injection did not significantly increase infection risk in any of the procedure subgroups.

CONCLUSIONS

The present study found no association between preoperative ESI within 30 days before surgery and postoperative infection in patients undergoing posterior cervical surgery.

The Role of Sex Hormones in Degenerative Disc Disease

STUDY DESIGN

Narrative review.

OBJECTIVES

The purpose of this review is to outline the role of sex hormones, particularly estrogen, in the pathogenesis of degenerative disc disease (DDD).

METHODS

A narrative review of studies discussing sex hormones and intervertebral disc (IVD) degeneration was conducted through a search of bibliographic databases to identify various mechanisms involved in effectuating DDD.

RESULTS

Estrogen-deficient states negatively impact various aspects of IVD function. These internal hormone environments reflect routine changes that commonly arise with physiologic aging and can compromise IVD structural integrity through a host of processes. Additionally, allosteric molecules such as micro-RNAs (mi-RNAs) and G protein-coupled estrogen receptors (GPER) antagonists can bind to estrogen receptors and inhibit protective downstream effects with estrogen receptor signaling. Furthermore, cursory studies have observed chondrogenic effects with testosterone supplementation, although the specific mechanism remains unclear.

CONCLUSIONS

Regulation of sex hormones, namely estrogen and testosterone, significantly impacts the structural integrity and function of IVDs. Uncovering underlying interactions driving these regulatory processes can facilitate development of novel, clinical therapies to treat DDD.

Nationwide Analysis of Sacroiliac Joint Fusion Trends: Regional Variations in Utilization and Population Characteristics

STUDY DESIGN/SETTING

Retrospective cohort analysis.

OBJECTIVES

This study evaluates utilization and demographic trends for sacroiliac joint (SIJ) fusions across the United States (US).

METHODS

Patients who underwent SIJ fusion from 2010-2021 were identified within the PearlDiver national database using International Classification of Disease (ICD-9, ICD-10) and Current Procedural Terminology (CPT) codes. Indications for trauma, malignancy, or infection were excluded. Demographic, clinical, and procedure characteristics were recorded along with annual utilization rates. Annual percent change (APC) was calculated to identify increasing or decreasing utilization from prior years. Negative binomial regression was performed to project subsequent utilization for 2022-2028. Chi-squared analysis followed by post-hoc comparisons were used to compare differences in diagnostic indications and clinical features associated with SIJ fusion across regions. Bonferroni adjustments were applied to P-values for pairwise analyses.

RESULTS

Overall, 18 032 patients (69.8% female, mean age = 51.0 + 13.4 years) underwent SIJ fusion between 2010 and 2021. Annual utilization increased by 33.5% on average. The South comprised the largest proportion of cases (48.9%). Projections for 2022-2028 predict continued growth in procedures, with an overall increase of 1100% from 1350 cases in 2021 to 16 195 by end of 2028. Spondyloarthropathy-induced sacroilitis was the most prevalent diagnostic indication nationwide (51%). Of patients undergoing SIJ fusion, 18% had a prior lumbar fusion, and only 45% received a preoperative diagnostic SIJ injection.

CONCLUSION

As SIJ fusion is increasingly utilized to treat refractory SIJ-based pain, establishing evidence-based guidelines, improving diagnostic strategies, and defining indications are imperative to support growing applications within clinical practice.

Preoperative Depression Screening in Primary Lumbar Fusion: An Evaluation of Its Modifiability on Outcomes in Patients with Diagnosed Depressive Disorder

OBJECTIVE

Studies have reported the detrimental effects of depression following spine surgery; however, none have evaluated whether preoperative depression screening in patients with a history of depression is protective from adverse outcomes and lowers health care costs. We studied whether depression screenings/psychotherapy visits within 3 months before 1- to 2-level lumbar fusion were associated with lower medical complications, emergency department utilization, readmissions, and health care costs.

METHODS

The PearlDiver database from 2010 to 2020 was queried for depressive disorder (DD) patients undergoing primary 1- to 2-level lumbar fusion. Two cohorts were 1:5 ratio matched and included DD patients with (n = 2,622) and DD patients without (n = 13,058) a preoperative depression screen/psychotherapy visit within 3 months of lumbar fusion. A 90-day surveillance period was used to compare outcomes. Logistic regression models computed odds ratio (OR) of complications and readmissions. P value < 0.003 was significant.

RESULTS

DD patients without depression screening had significantly greater incidence and odds of experiencing medical complications (40.57% vs. 16.00%; OR 2.71, P < 0.0001). Rates of emergency department utilization were increased in patients without screening versus screening (15.78% vs. 4.23%; OR 4.25, P < 0.0001), despite no difference in readmissions (9.31% vs. 9.53%; OR 0.97, P = 0.721). Finally, 90-day reimbursements ($51,160 vs. $54,731) were significantly lower in the screened cohort (all P < 0.0001).

CONCLUSIONS

Patients who underwent a preoperative depression screening within 3 months of lumbar fusion had decreased medical complications, emergency department utilization, and health care costs. Spine surgeons may use these data to counsel their patients with depression before surgical intervention.

Cemented versus Cementless Femoral Fixation for Elective Primary Total Hip Arthroplasty: A Nationwide Analysis of Short-Term Complication and Readmission Rates

Cementless fixation during total hip arthroplasty (THA) is the predominant mode of fixation utilized for both acetabular and femoral components during elective primary THAs performed in the United States. This study aims to compare early complication and readmission rates between primary THA patients receiving cemented versus cementless femoral fixation. The 2016-2017 National Readmissions Database was queried to identify patients undergoing elective primary THA. Postoperative complication and readmission rates at 30, 90, and 180 days were compared between cemented and cementless cohorts. Univariate analysis was conducted to compare differences between cohorts. Multivariate analysis was performed to account for confounding variables. Of 447,902 patients, 35,226 (7.9%) received cemented femoral fixation, while 412,676 (92.1%) did not. The cemented group was older (70.0 vs. 64.8, p < 0.001), more female (65.0% vs. 54.3%, p < 0.001), and more comorbid (CCI 3.65 vs. 3.22, p < 0.001) compared to the cementless group. On univariate analysis, the cemented cohort had decreased odds of periprosthetic fracture at 30 days postoperatively (OR: 0.556, 95%-CI 0.424-0.729, p < 0.0001), but higher odds of hip dislocation, periprosthetic joint infection, aseptic loosening, wound dehiscence, readmission, medical complications, and death at all timepoints. On multivariate analysis, the cemented fixation cohort demonstrated reduced odds of periprosthetic fracture at all postoperative timepoints: 30 (OR: 0.350, 95%-CI 0.233-0.506, p < 0.0001), 90 (OR: 0.544, 95%-CI 0.400-0.725, p < 0.0001), and 180 days (OR: 0.573, 95%-CI 0.396-0.803, p = 0.002). Cemented femoral fixation was associated with significantly fewer short-term periprosthetic fractures, but more unplanned readmissions, deaths, and postoperative complications compared to cementless femoral fixation in patients undergoing elective THA.

The Effect of Modifiable Risk Factors on Postoperative Complications in Lumbar Spine Fusions

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The impact of modifiable risk factors (MRFs) on complications, costs, and readmission rates at 30, 90, and 180-days following lumbar spine fusion.

METHODS

Patients with lumbar spine fusions within the 2016-2017 Nationwide Readmissions Database (NRD). Patients were stratified by the following MRFs: Alcohol use, tobacco/nicotine use, nutritional malnourishment, dyslipidemia, and primary hypertension. Differences in complications, non-elective readmission rates, costs, and length of stay were compared between MRFs and the non-MRF group. Statistical analysis was conducted using Tukey multiple comparisons of means, 1-way ANOVA, Wald testing, unpaired Welch 2-sample t-tests, multivariate analysis, and predictive modeling.

RESULTS

The final analysis included 297,579 lumbar fusion patients. At 30 and 90 days, patients with nutritional malnutrition, dyslipidemia, and primary hypertension had significantly greater readmission rates than patients without MRFs (all P<0.01). At 180-days, all MRFs had significantly greater readmission rates than the non-MRF group (all P<0.001). Dyslipidemia demonstrated significantly greater rates of myocardial infarction at 90 days compared to all groups (all P<0.02). Nutritional malnutrition was associated with a significantly greater mortality rate than primary hypertension, non-MRF, and tobacco/nicotine use at 90 days (P<0.001) and only tobacco/nicotine use at 180 days (P=0.007). Predictive modeling showed increases of 0.77%, 1.70%, and 2.44% risk of readmission at 30, 90, and 180-days respectively per additional MRF (all P<0.001).

CONCLUSIONS

These findings highlight the negative impact each MRF has on patients following lumbar spinal fusion. Further longitudinal research is necessary to comprehensively characterize the effects of various MRFs on spine surgery outcomes.

The Effect of COVID-19 on Spine Surgery

STUDY DESIGN/SETTING

Retrospective cohort analysis.

OBJECTIVES

To characterize the impact of COVID-19 on utilization of the ten most common spine procedures and percentages of outpatient procedures.

METHODS

The PearlDiver national database was queried from January 2010 to April 2021 for short (<6 segments) and long segment posterior instrumented fusion (≥6 segments), posterior cervical fusion, anterior cervical decompression and fusion (ACDF), cervical laminectomy, laminoplasty, and disc arthroplasty, lumbar laminectomy, microdiscectomy, and interbody fusion. Annual procedure utilization between January 2010 through April 2021 was recorded and compared. Monthly trends were compared to January 2020. Outpatient trends were compared between 2010-2019 and 2019-2021 using segmented linear regression.

RESULTS

Overall, all ten procedures decreased 4.3% in 2020 compared to 2019 and increased 6.3% in 2021 compared to 2019. March and April of 2020 had the largest decreases, with March 2020 decreasing 18.2% and April 2020 decreasing 51.6% compared to January 2020. Despite increasing COVID cases in January 2021, overall procedure utilization decreased only 1.8% compared to January 2020, and increased later in 2021 with April 2021 case volumes increasing by 138% compared to January 2020. Outpatient utilization of short segment posterior lumbar fusion and lumbar interbody fusion significantly increased during this time (P < .001).

CONCLUSION

The greatest impact on spine surgery volume from the COVID-19 pandemic occurred in March and April 2020. Spine procedure utilization was otherwise similar or increased compared to January 2020. Additionally, the volume of outpatient short segment posterior fusion and lumbar interbody fusions increased during this time period.

Postoperative Complication and Reoperation Rates Following Resection of Soft Tissue vs. Bone Malignancies Based on Anatomic Location in the Inpatient Setting

Introduction

Surgical excisions of upper and lower extremity malignancies are increasing annually, due in part to the rising incidence of sarcomas. The purpose of this study is to compare readmissions, reoperation rate, and complications following surgical excision of soft/connective tissue vs bone malignancies of the upper and lower extremities.

Methods

The Nationwide Readmissions Database (NRD) was queried from 2016-2017 to conduct a retrospective analysis of 16,435 patients diagnosed with malignant neoplasms of the long bone (ULLB, n = 1,433) and soft tissue (ULST, n = 2,049) of the upper limb and malignant neoplasms of the long bone (LLLB, n = 5,422) and soft tissue (LLST, n = 7,531) of the lower limb. Patients who underwent surgical excision of their neoplasms were included. Binomial multivariate logistic regression was used to compare complications, nonelective readmission rates, and reoperation rates between the two groups at 30 and 90 days.

Results

Average age of the ULST group was 61.88, with 36% female. Average age of the ULLB group was 44.97, with 41.90% female. Average age of the LLST group was 60.96, with 46.90% female. Average age of the LLLB group was 43.09, with 42.60% female. The ULST group had lower odds of readmission within 30 days (p=0.263), which became significant within 90 days of surgery (p=0.045). The LLST group had significantly higher odds of infection, reoperation within 30 to 90 days of the index surgery compared to the LLLB group (p < 0.0001). The LLST group had significantly lower odds of readmission within 30 (p=0.04) and 90 days (p=0.015) of the index surgery.

Conclusion

Patients in the ULST group had significantly lower odds of 90-day readmission compared to the ULLB group. There were also significantly lower odds of 30- and 90-day readmission in the LLST group compared to the LLLB group. However, the LLST group had significantly higher odds of infection and reoperation within 30 and 90 days compared to the LLLB group.

Radiographic Outcomes following ACDF with Hyperlordotic Implants to Achieve Cervical Anterior Column Realignment (ACR)

BACKGROUND

Degenerative disc disease and progressive sagittal malalignment can both contribute to degenerative cervical myelopathy and radiculopathy. For patients with symptoms refractory to conservative management, anterior cervical discectomy and fusion (ACDF) is a thoroughly vetted intervention shown to improve pain and disability measures. Hyperlordotic implants can also help restore cervical sagittal balance through anterior column realignment (ACR).

METHODS

A consecutive bi-institutional series of patients who underwent ACDF with hyperlordotic polyetheretherketone (PEEK) implants between 2014 and 2016 was reviewed. All included patients underwent ACDF between C3 and C7 inclusive of a hyperlordotic PEEK cervical implant (>10° lordosis), and had ≥12 months of radiographic follow-up. Lateral radiographs were analyzed to compare pre- and postoperative cervical parameters.

RESULTS

Forty-six patients were included (mean age, 58.0 years; male, 35%). Mean body mass index was 28.3 kg/m², and mean radiographic follow-up 14.4 months. Overall, cervical lordosis increased from -7.8° preoperatively to -14.8° postoperatively and to -15.7° at last follow-up (P < 0.001). Additionally, the mean segmental lordosis of ACR levels treated increased from -0.2° preoperatively to -4.8° postoperatively (P < 0.001), but no significant change was observed at last follow-up. Lastly, improvement in segmental lordosis was seen at both postoperative time points at the C3-C4 (P = 0.002 and P = 0.005, respectively), C4-C5 (P < 0.001 and P < 0.001, respectively), and C5-C6 levels (P < 0.001 and P < 0.001, respectively).

CONCLUSIONS

Our study demonstrates that hyperlordotic PEEK implants used for ACR effectively contribute to restoration of cervical lordosis in patients undergoing ACDF, potentially reducing the need for additional posterior surgery.

The impact of frailty on postoperative complications in geriatric patients undergoing multi-level lumbar fusion surgery

STUDY DESIGN

Retrospective Cohort Study.

PURPOSE

This study evaluates the impact of patient frailty status on postoperative complications in those undergoing multi-level lumbar fusion surgery.

METHODS

The Nationwide Readmission Database (NRD) was retrospectively queried between 2016 and 2017 for patients receiving multi-level lumbar fusion surgery. Demographics, frailty status, and relevant complications were queried at index admission and readmission intervals. Primary outcome measures included perioperative complications and 30-, 90-, and 180-day complication and readmission rates. Perioperative complications of interest were infection, urinary tract infection (UTI), and posthemorrhagic anemia. Secondary outcome measures included inpatient length of stay (LOS), adjusted all-payer costs, and discharge disposition. Nearest-neighbor propensity score matching for demographics was implemented to identify non-frail patients with similar diagnoses and procedures. Subgroup analysis of minimally invasive surgery (MIS) versus open surgery within frail and non-frail cohorts was conducted to evaluate differences in surgical and medical complication rates. The analysis used nonparametric Mann-Whitney U testing and odds ratios.

RESULTS

Frail patients encountered higher rates perioperative complications including posthemorrhagic anemia (OR: 1.73, 95%CI 1.50-2.00, p < 0.0001), infection (OR: 2.94, 95%CI 2.04-4.36, p < 0.0001), UTI (OR: 2.57, 95%CI 2.04-3.26, p < 0.0001), and higher rates of non-routine discharge (OR: 2.07, 95%CI 1.80-2.38, p < 0.0001). Frail patients had significantly greater LOS and total all-payer inpatient costs compared to non-frail patients (p < 0.0001). Frailty was associated with significantly higher rates of 90- (OR: 1.43, 95%CI 1.18-1.74, p = 0.0003) and 180-day (OR: 1.28, 95%CI 1.03-1.60, p = 0.02) readmissions along with higher rates of wound dehiscence (OR: 2.21, 95%CI 1.17-4.44, p = 0.02) at 90 days. Subgroup analysis revealed that frail patients were at significantly higher risk for surgical complications with open surgery (16%) compared to MIS (0%, p < 0.0001). No significant differences were found between surgical approaches with respect to medical complications in both cohorts, nor surgical complications in non-frail patients.

CONCLUSIONS

Frailty was associated with higher odds of all perioperative complications, LOS, and all-payer costs following multi-level lumbar fusion. Frail patients had significantly higher rates of 90 and 180-day readmission and higher rates of wound disruption at 90-days. On subgroup analysis, MIS was associated with significantly reduced rates of surgical complications specifically in frail patients. Our results suggest frailty status to be an important predictor of perioperative complications and long-term readmissions in geriatric patients receiving multi-level lumbar fusions. Frail patients should undergo surgery utilizing minimally invasive techniques to minimize risk of surgical complications. Future studies should explore the utility of implementing frailty in risk stratification assessments for patients undergoing spine surgery.

Complication Trends and Costs of Surgical Management in 11,086 Osteoporotic Patients Receiving Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to compare different aspects of fusion surgery in patients with osteoporosis with regard to graft subtype and surgical approach.

SUMMARY OF BACKGROUND DATA

Osteoporosis and chronic lower back pain are common in elderly populations and significantly increase the risk of compression fractures within the spine.

METHODS

Using the 2016-2017 National Readmission Database we identified 11,086 osteoporotic patients who received lumbar fusion using ICD-10 coding. Information regarding biologic graft type and surgical approach was collected. Patients were stratified by number of levels fused. Perioperative complications were collected at 30-, 90-, and 180-day follow-up intervals. Statistical analysis included univariate testing and multivariate regression modeling, controlling for patient demographics and comorbidities.

RESULTS

Patients receiving single-level fusion with autologous grafts had higher rates of hardware failure (P = 0.00014) at 30-day follow-up and 90-day follow-up (P < 0.0001) and higher rates of lumbar vertebral fractures at 90-day follow-up (P = 0.045) compared to those treated with nonautologous grafts. Patients receiving lumbar fusion with anterior and posterior approaches had no difference in readmission or infection rates, but the anterior approach was associated with a higher cost.

CONCLUSION

In this study, osteoporotic patients treated with autologous grafts had higher rates of complications compared to those treated with nonautologous grafts. Anterior and posterior approaches had similar complication rates; however, the anterior approach was associated with a higher total cost.Level of Evidence: 4.

Cemented Vs Cementless Femoral Fixation for Total Hip Arthroplasty After Displaced Femoral Neck Fracture: A Nationwide Analysis of Short-Term Complications and Readmission Rates

BACKGROUND

Active patients with displaced femoral neck fractures are often treated with total hip arthroplasty (THA). However, optimal femoral fixation in these patients is controversial. The purpose of this study was to compare early complication and readmission rates in patients with hip fracture treated with THA receiving cemented vs cementless femoral fixation.

METHODS

The National Readmissions Database was queried to identify patients undergoing primary THA for femoral neck fracture from 2016 to 2017. Postoperative complications and unplanned readmissions at 30, 90, and 180 days were compared between patients treated with cemented and cementless THA. Univariate and multivariate analyses were performed to compare differences between groups and account for confounding variables.

RESULTS

Of 17,491 patients identified, 4427 (25.3%) received cemented femoral fixation and 13,064 (74.7%) cementless. The cemented group was significantly older (77.2 vs 71.1, P < .001), had more comorbidities (Charlson comorbidity index: 4.44 vs 3.92, P < .001), and had a greater proportion of women (70.5% vs 65.2%, P < .001) compared with the cementless group. On multivariate analysis, cemented fixation was associated with reduced rates of periprosthetic fracture (odds ratio: 0.052, 95% confidence interval: 0.003-0.247, P = .004) at 30 days but similar readmission rates at 30, 90, and 180 days (odds ratio range: 1.012-1.114, P > .05) postoperatively compared with cementless fixation. Cemented fixation was associated with greater odds of medical complications at 180 days postoperatively (odds ratio:: 1.393, 95% confidence interval: 1.042-1.862, P = .025).

CONCLUSION

Cemented femoral fixation was associated with a lower short-term incidence of periprosthetic fractures, higher incidence of medical complications, and equivalent unplanned readmission rates within 180 days postoperatively compared with cementless fixation in patients undergoing THA for femoral neck fracture.

LEVEL OF EVIDENCE

Level III.

Impact of diagnosis and type of sacroiliac joint fusion on postoperative complications

PURPOSE

Two main surgical approaches are available for fusing the sacroiliac joint (SIJ): an open or minimally invasive (MIS) approach. The purpose of this study was to analyze the associated total hospital charges and postoperative complications of the MIS and open approach.

METHODS

Using the 2016 and 2017 National Readmission Database, we conducted a retrospective cohort analysis of 2521 patients who received a SIJ fusion with an open (N = 1990) or MIS (N = 531) approach for diagnosed sacrum pain, sacroiliitis, sacral instability, or spondylosis. Each cohort was analyzed for postoperative complications.

RESULTS

We identified 604 patients diagnosed with sacrum pain, 1142 with sacroiliitis, 315 with spondylosis, and 288 with sacral instability. Patients who received the open approach for sacrum pain had significantly higher rates of novel post-procedural pain (p = 0.045) and novel lumbar pathology (p = 0.015) within 30 days. On 30-day follow-up, patients with sacroiliitis treated with open SIJ fusion had significantly higher rates of novel postprocedural pain compared to those treated with MIS fusion (p = 0.045). Patients who received the open approach for spondylosis resulted in significantly higher rates of non-elective readmission within 30 days compared to the MIS approach (p < 0.0001). In addition, the open technique for spondylosis resulted in significantly higher rates of non-elective readmissions for infection within 30 days (p = 0.014). On 30-day follow-up, patients with sacral instability treated with open SIJ fusion had significantly higher rates of UTI (p = 0.045).

CONCLUSION

Our study suggests that there exist unique postoperative complications that arise after SIJ fusion specific to preoperative diagnosis and surgical approach.

Propensity-matched Analysis of 1062 Patients Following Minimally Invasive Versus Open Sacroiliac Joint Fusion

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The aim of this study was to compare the hospital charges and postoperative complications of minimally invasive surgery (MIS) and open approaches to sacroiliac joint (SIJ) fusion.

SUMMARY OF BACKGROUND DATA

The data source utilized in this study is the Healthcare Cost and Utilization Project National Readmission Database (NRD) from 2016 and 2017. The NRD is a yearly nationally representative inpatient database from the Agency for Healthcare Research and Quality with information regarding patient demographics, diagnoses, procedures, and readmissions.

MATERIALS AND METHODS

The 2016-2017 NRD was used to identify 2521 patients receiving SIJ fusion with open (n=1990) or MIS approaches (n=531) for diagnosed sacrum pain, sacroiliitis, sacral instability, or spondylosis after excluding for those who received prior SIJ fusion, those diagnosed with neoplasms or trauma of the pelvis or sacrum, and nonelective procedures. We then one-to-one propensity-matched the open (n=531) to the MIS approach (n=531) for age, sex, and Charlson Comorbidity Index. Statistical analysis was performed to compare total hospital charges, immediate surgical complications, nonelective readmission rate, and 30-, 90-, and 180-day postoperative complications between the 2 approaches.

RESULTS

The mean total hospital charge was the only significant difference between 2 group. Open SIJ fusion had significantly higher charge compared with the MIS approach (open $101,061.90±$81,136.67; MIS $83,594.78±$49,086.00, P<0.0001). The open approach was associated with nonsignificant higher rates of novel lumbar pathology at 30-, 90-, and 180-day readmissions and revision surgeries at 30 and 180 days. MIS approach had higher rates nervous system complications at 30-, 90-, and 180-day readmission, as well as infection and urinary tract infection within 30 days, none being significant. Novel postprocedural pain was similar between the 2 groups at 90 and 180 days.

CONCLUSIONS

The current study found that open SIJ fusion was associated with significantly higher hospital charges. Although no significant differences in postoperative complications were found, there were several notable trends specific to each surgical approach.

The role of frailty in geriatric cranial neurosurgery for primary central nervous system neoplasms

OBJECTIVE

Frailty is a clinical state of increased vulnerability due to age-associated decline and has been well established as a perioperative risk factor. Geriatric patients have a higher risk of frailty, higher incidence of brain cancer, and increased postoperative complication rates compared to nongeriatric patients. Yet, literature describing the effects of frailty on short- and long-term complications in geriatric patients is limited. In this study, the authors evaluate the effects of frailty in geriatric patients receiving cranial neurosurgery for a primary CNS neoplasm.

METHODS

The authors conducted a retrospective cohort study of geriatric patients receiving cranial neurosurgery for a primary CNS neoplasm between 2010 and 2017 by using the Nationwide Readmission Database. Demographics and frailty were queried at primary admission, and readmissions were analyzed at 30-, 90-, and 180-day intervals. Complications of interest included infection, anemia, infarction, kidney injury, CSF leak, urinary tract infection, and mortality. Nearest-neighbor propensity score matching for demographics was implemented to identify nonfrail control patients with similar diagnoses and procedures. The analysis used Welch two-sample t-tests for continuous variables and chi-square test with odds ratios.

RESULTS

A total of 6713 frail patients and 6629 nonfrail patients were identified at primary admission. At primary admission, frail geriatric patients undergoing cranial neurosurgery had increased odds of developing acute posthemorrhagic anemia (OR 1.56, 95% CI 1.23-1.98; p = 0.00020); acute infection (OR 3.16, 95% CI 1.70-6.36; p = 0.00022); acute kidney injury (OR 1.32, 95% CI 1.07-1.62; p = 0.0088); urinary tract infection prior to discharge (OR 1.97, 95% CI 1.71-2.29; p < 0.0001); acute postoperative cerebral infarction (OR 1.57, 95% CI 1.17-2.11; p = 0.0026); and mortality (OR 1.64, 95% CI 1.22-2.24; p = 0.0012) compared to nonfrail geriatric patients receiving the same procedure. In addition, frail patients had a significantly increased inpatient length of stay (p < 0.0001) and all-payer hospital cost (p < 0.0001) compared to nonfrail patients at the time of primary admission. However, no significant difference was found between frail and nonfrail patients with regard to rates of infection, thromboembolism, CSF leak, dural tear, cerebral infarction, acute kidney injury, and mortality at all readmission time points.

CONCLUSIONS

Frailty may significantly increase the risks of short-term acute complications in geriatric patients receiving cranial neurosurgery for a primary CNS neoplasm. Long-term analysis revealed no significant difference in complications between frail and nonfrail patients. Further research is warranted to understand the effects and timeline of frailty in geriatric patients.

The Influence of Body Mass Index in Obese and Morbidly Obese Patients on Complications and 30- and 90-day Readmissions Following Lumbar Spine Fusion

STUDY DESIGN

Retrospective cohort study using the 2013-2017 National Readmission Database.

OBJECTIVE

The aim of this study was to quantify the influence of body mass index (BMI) on complication and readmission rates following lumbar spine fusion.

SUMMARY OF BACKGROUND DATA

Compared to controls, patients with BMI ≥35 had greater odds of readmission, infection, and wound complications following lumbar spine fusion.

METHODS

Patients who underwent elective lumbar spine fusion within the population-based sample were considered for inclusion. Exclusion criteria included nonelective lumbar spine fusions, malnourished, anorexic, or underweight patients, and surgical indications of trauma or neoplasm. Patients were grouped by BMI: 18.5 to 29.9 (controls), 30 to 34.9 (obesity I), 35 to 39.9 (obesity II), and ≥40 (obesity III). Multivariate regression was performed to analyze differences in complications and readmissions between groups. Predictive modeling was conducted to estimate the impact of BMI on 30- and 90-day infection, wound complication, and readmissions rates.

RESULTS

A total of 86,697 patients were included for analysis, with an average age of 58.9 years and 58.9% being female. The obesity II group had significantly higher odds of infection (odds ratio [OR]: 1.82, 95% confidence interval [CI]: 1.28-2.62, P = 0.001), wound dehiscence (OR: 3.08, 95% CI: 1.70-6.18, P = 0.0006), and 30-day readmission (OR: 1.32, 95% CI: 1.11-1.58, P = 0.002), whereas the obesity III group had significantly higher odds of acute renal failure (OR: 2.14, 95% CI: 1.20-4.06, P = 0.014), infection (OR: 2.43, 95% CI: 1.72-3.48, P < 0.0001), wound dehiscence (OR: 3.76, 95% CI: 2.08-7.51, P < 0.0001), 30-day readmission (OR: 1.62, 95% CI: 1.36-1.93, P < 0.0001), and 90-day readmission (OR: 1.53, 95% CI: 1.31-1.79, P < 0.0001) compared with controls. Predictive modeling showed cumulative increases of 6.44% in infection, 3.69% in wound dehiscence, and 1.35% in readmission within 90-days for each successive BMI cohort.

CONCLUSION

Progressively higher risks for infection, wound complications, and hospital readmission were found with each progressive BMI level.Level of Evidence: 3.

The Impact of Osteobiologic Subtype Selection on Perioperative Complications and Hospital-Reported Charges in Single- and Multi-Level Lumbar Spinal Fusion

BACKGROUND

Over the last several decades, various osteobiologics including allograft, synthetics, and growth factors have been used for lumbar spinal fusion surgery. However, the data on these osteobiologic products remain controversial with conflicting evidence in the literature. This study evaluates the influence of osteobiologic type selection on perioperative complications and hospital-reported charges in single-level and multilevel lumbar fusion.

METHODS

Using the 2016 and 2017 Nationwide Readmission Database, we conducted a retrospective cohort analysis of 125,143 patients who received lumbar fusion with either autologous tissue substitute, nonautologous tissue substitute, or synthetic substitute. This cohort was split into single-level and multilevel fusion procedures, and one-to-one age and sex propensity score matching was implemented. This resulted in cohorts each consisting of 1967 patients for single-level fusion, and cohorts each consisting of 1657 patients for multilevel fusion. Statistical analysis included one-way analysis of variance and Tukey multiple comparisons of means.

RESULTS

Autologous single-level fusion resulted in significantly more postoperative pain at 30-, 90-, and 180-day follow-up compared to fusion with nonautologous graft (P < .05). Multilevel fusion with autologous graft had higher rates of acute postsurgical anemia compared with synthetic (P = .021) and nonautologous (P = .016) alternatives, and less postsurgical infection when compared with nonautologous fusion (P = .0020). In addition, procedures using autologous osteobiologics were associated with significantly more neurological complications at 30 days (P = .049) and 90 days (P = .048) for multi-level fusion and at 30 days (P = .044) for single-level fusion compared with the nonautologous group. Lastly, for both cohorts, the total accrued inpatient hospital charges during admission for patients receiving nonautologous grafts were the most expensive and those for patients receiving autologous grafts were the least expensive.

CONCLUSION

Significant differences were found between the groups with respect to rates of complications, including infection, postoperative pain, and neurologic injury. Furthermore, the hospital-reported charges of each procedure varied significantly. As the field of biologics continues to expand, it is important to continually evaluate the safety, efficacy, and cost-effectiveness of these novel materials and techniques.

LEVEL OF EVIDENCE

3 CLINICAL RELEVANCE: With increased utilization of osteobiologics and spinal fusion being a common procedure, longitudinal data on readmissions, and post-operative complications are critical in guiding evidence-based practice.

Inclusion of Frailty Improves Predictive Modeling for Postoperative Outcomes in Surgical Management of Primary and Secondary Lumbar Spine Tumors

BACKGROUND

Malignant spinal tumors are common, continually increasing in incidence as a function of improved survival times for patients with cancer. Using predictive analytics and propensity score matching, we evaluated the influence of frailty on postoperative complications compared with age in patients with malignant neoplasms of the lumbar spine.

METHODS

We used the Nationwide Readmissions Database from 2016 and 2017 to identify patients with malignant neoplasms of the lumbar spine who received a fusion procedure. Patient frailty was queried using the Johns Hopkins Adjusted Clinical Groups. Propensity score matching for age, sex, Charlson Comorbidity Index, surgical approach, and number of levels fused was implemented between frail and nonfrail patients, identifying 533 frail patients and 538 nonfrail patients. The area under the curve (AUC) of each ROC served as a proxy for model performance.

RESULTS

Frail patients reported significantly higher inpatient lengths of stay, costs, infection, posthemorrhagic anemia, and urinary tract infections (P < 0.05). In addition, frail patients were more often discharged to skilled nursing facilities and short-term hospitals compared with nonfrail patients (P < 0.0001). Regression models for mortality (AUC = 0.644), nonroutine discharge (AUC = 0.600), and acute infection (AUC = 0.666) were improved when using frailty as the primary predictor. These models were also improved using frailty when predicting 30-day readmission and 90-day hardware failure.

CONCLUSIONS

Frailty demonstrated a significant relationship with increased postoperative patient complications, length of stay, costs, and acute complications in patients receiving fusion following resection of a malignant neoplasm of the lumbar spine region. Frailty demonstrated better predictive validity of outcomes compared with patient age.

The influence of modifiable risk factors on short-term postoperative outcomes following cervical spine surgery: A retrospective propensity score matched analysis

BACKGROUND

Modifiable risk factors (MRFs) represent patient variables associated with increased complication rates that may be prevented. There exists a paucity of studies that comprehensively analyze MRF subgroups and their independent association with postoperative complications in patients undergoing cervical spine surgery. Therefore, the purpose of this study is to compare outcomes between patients receiving cervical spine surgery with reported MRFs.

METHODS

Retrospective analysis of the Nationwide Readmissions Database (NRD) from the years 2016 and 2017, a publicly available and purchasable data source, to include adult patients undergoing cervical fusion. MRF cohorts were separated into three categories: substance abuse (alcohol, tobacco/nicotine, opioid abuse); vascular disease (hypertension, dyslipidemia); and dietary factors (malnutrition, obesity). Three-way nearest-neighbor propensity score matching for demographics, hospital, and surgical characteristics was implemented.

FINDINGS

We identified 9601 with dietary MRFs (D-MRF), 9654 with substance abuse MRFs (SA-MRF), and 9503 with vascular MRFs (V-MRF). Those with d-MRFs had significantly higher rates of medical complications (9.3%), surgical complications (8.1%), and higher adjusted hospital costs compared to patients with SA-MRFs and V-MRFs. Patients with d-MRFs (16.3%) and V-MRFs (14.0%) were independently non-routinely discharged at a significantly higher rate compared to patients with SA-MRFs (12.6%) (p<0.0001 and p = 0.0037). However, those with substance abuse had the highest readmission rate and were more commonly readmitted for delayed procedure-related infections.

INTERPRETATION

A large proportion of patients who receive cervical spine surgery have potential MRFs that uniquely influence their postoperative outcomes. A thorough understanding of patient-specific MRF subgroups allows for improved preoperative risk stratification, tailored patient counseling, and postoperative management planning.

FUNDING

None.

Identifying risks factors in thoracolumbar anterior fusion surgery through predictive analytics in a nationally representative inpatient sample

PURPOSE

Anterior thoracolumbar (TL) surgical approaches provide more direct trajectories compared to posterior approaches. Proper patient selection is key in identifying populations that may benefit from anterior TL fusion. Here, we utilize predictive analytics to identify risk factors in anterior TL fusion in patients with trauma and deformity.

METHODS

In this retrospective cohort study of patients receiving anterior TL fusion (between and including T12/L1), population-based regression models were developed to identify risk factors using the National Readmission Database 2016-2017. Readmissions were analyzed at 30- and 90-day intervals. Risk factors included hypertension, obesity, malnutrition, smoking, alcohol use, long-term opioid use, and frailty. Multivariate regression models were developed to determine the influence of each risk factor on complication rates.

RESULTS

A total of 265 and 375 patients were identified for the scoliosis and burst fracture cohorts, respectively. In patients with scoliosis, alcohol use was found to increase the length of stay (LOS) (p = 0.00061) and all-payer inpatient cost following surgery (p = 0.014), and frailty was found to increase the inpatient LOS (p = 0.0045). In patients with burst fractures, malnutrition was found to increase the LOS (p < 0.0001) and all-payer cost (p < 0.0001), obesity was found to increase the all-payer cost (p = 0.012), and frailty was found to increase the all-payer cost (p = 0.031) and LOS (p < 0.0001).

DISCUSSION

Patient-specific risk factors in anterior TL fusion surgery significantly influence complication rates. An understanding of relevant risk factors before surgery may facilitate preoperative patient selection and postoperative patient triage and risk categorization.

Demographic-Dependent Risk of Developing Severe Novel Psychiatric Disorders after Concussion

Current guidelines for patients experiencing a concussion or mild traumatic brain injury (mTBI) often focus on conservative care and observation. However, mTBI may increase the risk of severe novel psychiatric disorders (NPDs) within 180 days, and long-term management of mTBI should include psychiatric evaluation in patient populations. Retrospective cohort analysis was conducted using 8 years of the Nationwide Readmission Database. All individuals who were admitted for concussion and were readmitted within 180 days were queried. This cohort was then subdivided based on age, sex, and whether they experienced loss of consciousness (LOC) to control for demographic-dependent confounding. A binary decision tree provided recommendations for patients who may be at risk of developing severe NPDs. Analysis included 12,080 patients who experienced concussion. Males and females with LOC had higher rates of depression in all age quartiles within 180 days (p < 0.05). Young females with LOC had increased rates of suicidal ideation (p < 0.01), and those >25 years of age had increased rates of anxiety (p < 0.005). Adult males with LOC had increased rates of suicidal ideation (p < 0.002) and males >75 years of age had increased rates of anxiety at readmission (p < 0.05). Males without LOC had increased rates of depression (p < 0.005), with men in the second quartile also at higher risk of developing anxiety (p < 0.05). Females without LOC showed the fewest number of NPDs at readmission. Concussion may be associated with increased rates of NPDs in the first 6 months following discharge. We use these data to develop recommendations for psychiatric screening of patients with mTBI.

Indication-based analysis of patient outcomes following deep brain stimulation surgery

BACKGROUND

While considered a safe operation, deep brain stimulation (DBS) has been associated with various morbidities. We assessed differences in postsurgical complication rates in patients undergoing the most common types of neurostimulation surgery.

METHODS

The National Readmission Database (NRD) was queried to identify patients undergoing neurostimulation placement with the diagnosis of Parkinson disease (PD), epilepsy, dystonia, or essential tremor (ET). Demographics and complications, including infection, pneumonia, and neurostimulator revision, were queried for each cohort and compiled. Readmissions were assessed in 30-, 90-, and 180-day intervals. We implemented nearest-neighbor propensity score matching to control for demographic and sample size differences between groups.

RESULTS

We identified 3230 patients with Parkinson disease, 1289 with essential tremor, 965 with epilepsy, and 221 with dystonia. Following propensity score matching, 221 patients remained in each cohort. Readmission rates 30-days after hospital discharge for PD patients (15.5 %) were significantly greater than those for ET (7.8 %) and seizure patients (4.4 %). Pneumonia was reported for PD (1.6 %), seizure (3.3 %) and dystonia (1.7 %) patients but not individuals ET. No PD patients were readmitted at 30-days due to dysphagia while individuals treated for ET (6.5 %), seizure (1.6 %) and dystonia (5.2 %) were. DBS-revision surgery was performed for 11.48 % of PD, 6.52 % of ET, 1.64 % of seizure and 6.90 % of dystonia patients within 30-days of hospital discharge.

CONCLUSION

30-day readmission rates vary significantly between indications, with patients receiving DBS for PD having the highest rates. Further longitudinal studies are required to describe drivers of variation in postoperative outcomes following DBS surgery for different indications.

Comparison of Proximal Junctional Failure and Functional Outcomes Across Varying Definitions of Proximal Junctional Kyphosis

BACKGROUND

Proximal junctional kyphosis (PJK) is a well-recognized complication following surgery for adult spinal deformity (ASD); however, definitions for PJK and its clinical implications can significantly vary by study. This study compares multiple definitions of PJK and describes incidence and clinical significance by definition.

METHODS

From 2014 to 2019, patients with ASD who underwent spinal fusion were identified. Nine definitions of PJK were created based on previously established definitions using the following upper instrumented vertebra +2 (UIV+2) sagittal Cobb measurements: A= ≥10 postoperative AND preoperative, B = ≥10 postoperative, C = ≥10 preoperative, D = ≥15 postoperative AND preoperative, E = ≥15 postoperative, F = ≥15 preoperative, G = ≥20 postoperative AND preoperative, H = ≥20 postoperative, I = >20 preoperative. Incidence of PJK was calculated by definition. Area under the curve (AUC) was calculated based on a receiver operating characteristic to assess ability to predict proximal junctional failure (PJF). Univariate analysis was performed to assess association with postoperative Oswestry Disability Index (ODI) scores.

RESULTS

Across 82 patients, the incidence of PJK and AUC by definition was as follows: A = 47%, 0.47; B = 72%, 0.65; C = 49%, 0.45; D = 27%, 0.46; E = 57%, 0.62; F = 27%, 0.46; G = 10%, 0.55; H = 40%, 0.71; I = 10%, 0.55. No definition was associated with postoperative ODI scores (P < 0.05).

CONCLUSIONS

The incidence of PJK significantly decreased with stricter definitions. Definitions utilizing only postoperative UIV+2 values had higher incidences but were more likely to capture patients who developed PJF. No definition was associated with postoperative ODI scores. UIV+2 ≥20 was best in distinguishing patients who developed PJF.

Analysis of modifiable and nonmodifiable risk factors in patients undergoing pituitary surgery

OBJECTIVE

Pituitary adenomas (PAs) are among the most common intracranial tumors. Understanding the clinical effects of various modifiable risk factors (MRFs) and nonmodifiable risk factors (NMRFs) is important in guiding proper treatment, yet there is limited evidence outlining the influence of MRFs and NMRFs on outcomes of PA resection. The aim of this study was to analyze MRFs and NMRFs in patients undergoing resection for PAs.

METHODS

Using the 2016 and 2017 National Readmission Database, the authors identified a cohort of 9472 patients undergoing microscopic or endoscopic resection of a PA. Patients with nonoverlapping MRFs and NMRFs were analyzed for length of stay (LOS), hospital cost, readmission rates, and postoperative complications. From the original cohort, a subset of 373 frail patients (as defined by the Johns Hopkins Frailty Index) were identified and propensity matched to nonfrail patients. Statistical analysis included 1-way ANOVA, Tukey multiple comparisons of means, odds ratios, Wald testing, and unpaired Welch 2-sample t-tests to compare complications, outcomes, and costs between each cohort. Perioperative outcomes and hospital readmission rates were tracked, and predictive algorithms were developed to establish precise relationships between relevant risk factors and neurosurgical outcomes.

RESULTS

Malnourished patients had significantly longer LOSs when compared to nonmalnourished patients (p < 0.001). There was a significant positive correlation between the number of MRFs and readmission at 90 days (p = 0.012) and 180 days (p = 0.020). Obese patients had higher rates of postoperative neurological injury at the 30-day follow-up (p = 0.048) compared to patients with normal BMI. Within this NMRF cohort, frail patients were found to have significantly increased hospital LOS (p < 0.001) and total inpatient costs compared to nonfrail patients (p < 0.001). Predictive analytics showed that frail patients had significantly higher readmission rates at both 90-day (p < 0.001) and 180-day follow-ups (p < 0.001). Lastly, rates of acute postsurgical infection were higher in frail patients compared to nonfrail patients (p < 0.001).

CONCLUSIONS

These findings suggest that both MRFs and NMRFs negatively affect the perioperative outcomes following PA resection. Notable risk factors including malnutrition, obesity, elevated lipid panels, and frailty make patients more prone to prolonged LOS, higher inpatient costs, and readmission. Further prospective research with longitudinal data is required to precisely pinpoint the effects of various risk factors on the outcomes of pituitary surgery.

Complications following operative treatment of supination-adduction type II (AO/OTA 44A2.3) ankle fractures

INTRODUCTION

There are few published studies that investigate the surgical treatment of supination-adduction (SAD, AO/OTA 44A2.3) ankle fractures. The purpose of this study was to describe the complications and outcomes following operative fixation of SAD type 2 ankle fractures.

MATERIALS AND METHODS

We identified all SAD-2 ankle fractures that presented at our institution's two hospitals from 2006-2018. Demographics, operative data, and complications (deep infection, superficial infection, delayed union, failure of fixation, and unplanned reoperation) were recorded for all patients. Lastly, all included patients were contacted by telephone for the administration of an 8-question Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) and Pain Interference questionnaire (PI). Univariate and multivariate analysis was performed to identify risk factors for complication or poor functional outcome score.

RESULTS

65 patients met inclusion criteria. The average time to surgery was 14 days and average follow-up was 20.5 (range: 0.4-60.9) weeks. There were 9 (13.8%) complications (4 deep infections, 3 superficial infections, 1 delayed union, 1 failure of fixation) and 6 unplanned reoperations. Univariate and multivariate analysis failed to identify any statistically significant risk factors for complication or reoperation. Eleven patients participated in the administration of PROMIS score questionnaires at a mean of 3.4 years postoperatively. The average PROMIS Physical Function T-score was 42.3 ± 11.3 and the average PROMIS Pain Interference T-score was 55.8 ± 7.8. Younger age was associated with a higher physical function score. The use of a direct medial approach to the medial malleolus was associated with a lower pain interference score.

CONCLUSION

The overall complication rate for SAD (OTA/AO 44A2.3) type 2 ankle fractures is similar to that of the general ankle fracture population. We were unable to identify risk factors for complication or reoperation. Mean patient reported outcomes are within one standard deviation of the general population.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Utility of 18F-fluoroestradiol (18F-FES) PET/CT imaging as a pharmacodynamic marker in patients with refractory estrogen receptor-positive solid tumors receiving Z-endoxifen therapy

BACKGROUND

Z-endoxifen is the most potent of the metabolites of tamoxifen, and has the potential to be more effective than tamoxifen because it bypasses potential drug resistance mechanisms attributable to patient variability in the expression of the hepatic microsomal enzyme CYP2D6. ¹⁸F-FES is a positron emission tomography (PET) imaging agent which selectively binds to estrogen receptor alpha (ER-α) and has been used for non-invasive in vivo assessment of ER activity in tumors. This study utilizes ¹⁸F-FES PET imaging as a pharmacodynamic biomarker in patients with ER+ tumors treated with Z-endoxifen.

METHODS

Fifteen patients were recruited from a parent therapeutic trial of Z-endoxifen and underwent imaging with ¹⁸F-FES PET at baseline. Eight had positive lesions on the baseline scan and underwent follow-up imaging with ¹⁸F-FES 1-5 days post administration of Z-endoxifen.

RESULTS

Statistically significant changes (p = 0.0078) in standard uptake value (SUV)-Max were observed between the baseline and follow-up scans as early as 1 day post drug administration.

CONCLUSION

F-FES PET imaging could serve as a pharmacodynamic biomarker for patients treated with ER-directed therapy.

Dynamic contrast-enhanced T2*-weighted MR imaging of tumefactive demyelinating lesions

PURPOSE

Dynamic contrast-enhanced T2*-weighted MR imaging has been helpful in characterizing intracranial mass lesions by providing information on vascularity. Tumefactive demyelinating lesions (TDLs) can mimic intracranial neoplasms on conventional MR images, can be difficult to diagnose, and often result in surgical biopsy for suspected tumor. The purpose of this study was to determine whether dynamic contrast-enhanced T2*-weighted MR imaging can be used to distinguish between TDLs and intracranial neoplasms that share common features on conventional MR images.

METHODS

We retrospectively reviewed the conventional and dynamic contrast-enhanced T2*-weighted MR images and medical records of 10 patients with tumefactive demyelinating disease that was diagnosed by either biopsy or strong clinical suspicion supported by laboratory evaluation that included CSF analysis and evoked potential tests. Twelve TDLs in 10 patients and 11 brain tumors that appeared similar on conventional MR images were studied. Relative cerebral blood volume (rCBV) was calculated from dynamic MR data and was expressed as a ratio to contralateral normal white matter. rCBV values from 11 patients with intracranial neoplasms with very similar conventional MR imaging features were used for comparison.

RESULTS

The rCBV values of TDLs ranged from 0.22 to 1.79 (n = 12), with a mean of 0.88 +/- 0.46 (SD). The rCBV values of intracranial neoplasms ranged from 1.55 to 19.20 (n = 11), with a mean of 6.47 +/- 6.52. The difference in rCBV values between the two groups was statistically significant (P =.009). The difference in rCBV values between TDLs and primary cerebral lymphomas (n = 4) was less pronounced but was statistically significant (P =.005).

CONCLUSION

Dynamic contrast-enhanced T2*-weighted MR imaging is a useful diagnostic tool in differentiating TDLs from intracranial neoplasms and may therefore obviate unnecessary surgical biopsy.

Image content extraction: application to MR images of the brain

A system for automatically extracting image content features was developed that combines registration to a labeled atlas with natural language processing of free-text radiology reports. The system was then tested with T1-weighted, spoiled gradient-echo magnetic resonance (MR) imaging studies of the brain performed in nine patients. The locations of 599 structures were visually assessed by an experienced radiologist and compared with the locations indicated by automated output. The in-plane accuracy of the contours was subjectively evaluated as either good, moderate, or poor. The criterion for classifying a structure as correctly located was that 90% or more of all the images containing the structure had to be correctly identified. For 98% of the structures, the images identified by the automated algorithm agreed with those identified by the radiologist, and in 83% of cases, image contours showed a good in-plane overlap. The results of this validation study demonstrate that this combination of registration and natural language processing is accurate in identifying relevant images from brain MR imaging studies. However, the range of applicability of this technique has yet to be determined by applying the technique to a large number of studies.