30-day Mortality Following Surgery for Spinal Epidural Abscess: Incidence, Risk Factors, Predictive Algorithm, and Associated Complications

Long-term survivability of surgical and nonsurgical management of spinal epidural abscess

BACKGROUND CONTEXT

Spinal epidural abscess (SEA) is a rare and life-threatening infection within the epidural space with significant functional impairment and morbidity. Active debate remains over whether to operate for SEAs, with limited existing data comparing the long-term survivability after surgical versus nonsurgical management.

PURPOSE

This study aims to determine the long-term survival of patients who underwent surgical and nonsurgical management for SEA.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

A total of 250 consecutive SEA patients.

OUTCOME MEASURES

Survival and mortality rates, complications.

METHODS

All patients treated at a tertiary medical center for a primary SEA from January 2000 to June 2020 are identified. Data collection is by retrospective chart review. Cox proportional hazards regression models are used for all survival analyses while controlling for potential confounding variables and with multiple testing corrections.

RESULTS

A total of 35 out of 250 patients died with an overall all-cause mortality of 14%. More than half of all deaths occurred within 90 days after treatment. The 90-day, 3-year, and 5-year survival rates are 92.8%, 89.2%, and 86.4%, respectively. Among surgery patients, the all-cause mortality was 13.07%, compared to 16.22% for medically-managed patients. Surgical treatment (decompression, fusion, debridement) significantly reduced the risk of death by 62.4% compared to medical therapy (p=.03), but surgery patients experienced a significantly longer mean length of stay (p=.01). Risk factors of short-term mortality included hypoalbuminemia (<3.5 g/dL), American Society of Anesthesiologists (ASA) 4+, and cardiac arrest. Risk factors of long-term mortality were immunocompromised state, elevated WBC count >12,000, sepsis, septic shock, ASA 4+, and cardiac arrest (p<.05). In terms of complications, surgically-managed patients experienced a higher proportion of deep vein thrombosis (p<.05).

CONCLUSIONS

The overall long-term survivability of SEA treatment is relatively high at (86% at 5-year) in this study. The following SEA mortality risk factors were identified: hypoalbuminemia (short-term), immunocompromised state (long-term), leukocytosis (long-term), sepsis and septic shock (long-term), ASA 4+ and cardiac arrest (overall). For primary SEA patients, surgical management may reduce mortality risk compared to nonsurgical management.

Long-term quality of life and functional outcomes after management of spinal epidural abscess

BACKGROUND/CONTEXT

In recent years, the incidence of spinal epidural abscesses (SEA) has tripled in number and nonoperative management has risen in popularity. While there has been a shift towards reserving surgical intervention for patients with focal neurologic deficits, a third of patients will still fail medical management and require surgical intervention. Failure to understand long-term quality of life and functional outcomes hinders effective decision making and prognostication.

PURPOSE

To describe patterns and associated factors impacting long-term quality of life following treatment of spinal epidural abscess.

STUDY DESIGN/SETTING

Multicenter cohort study at two urban academic tertiary referral centers and two community centers.

PATIENT SAMPLE

Adult patients treated for a spinal epidural abscess.

OUTCOME MEASURES

EuroQoL 5-Dimension 5L (EQ5D), Neuro-Quality of Life Lower Extremity - Mobility (Short Form; NeuroQoL-LE), Patient-Reported Outcomes Measurement Information System Physical Function (short form 4a; PROMIS PF), and PROMIS Global Mental Health score (PROMIS Mental).

METHODS

Eligible patients were enrolled and administered questionnaires. Multivariable analysis assessed the influence of ambulatory status on HRQL, adjusting for covariates including age, biologic sex, Charlson comorbidity index, intravenous drug use, management approach, and ASIA grade on presentation.

RESULTS

Sixty-one patients were enrolled (mean age 60.5 years, 46% male). Thirty-four patients (58%) underwent operative management. Mean standard deviation (SD) results for HRQL measures were: EQ5D 0.51 (0.37), EQ5D visual analogue scale 60.34 (25.11), NeuroQoL Lower extremity 41.47 (10.64), PROMIS physical function 39.49 (10.07), and PROMIS Global Mental Health 44.23 (10.36). Adjusted analysis demonstrated ambulatory status at presentation, and at 1 year, to be important drivers of HRQL, irrespective of other factors including IVDU and ASIA grade. Patients with independent ambulatory function at 1 year had mean EQ5D utility of 0.65 (95% CI 0.55, 0.75), whereas those requiring assistive devices saw a 49% decrease with mean EQ5D utility of 0.32 (0.14, 0.51). Ambulatory status was associated with global and physical function but did not impact overall health self-assessment or mental health scores.

CONCLUSIONS

We found that ambulatory status was the most important factor associated with long-term HRQL regardless of other factors such as ASIA grade or IVDU. Given prior literature demonstrating the protective effect of operative intervention on ambulatory function, this highlights ambulatory dysfunction as a potential indication for surgery and a marker of poor long-term prognosis, even in the absence of focal neurologic deficits. Our work also highlights the importance of optimized long-term rehabilitation strategies aimed to preserve ambulatory function in this high-risk population.

LEVEL OF EVIDENCE

Level III, cohort study.

Risk Factors for Readmission Following Surgical Decompression for Spinal Epidural Abscesses: An Analysis of 4595 Patients

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The study aimed to (1) compare baseline demographics of patients undergoing surgery for SEA who were/were not readmitted; (2) identify risk factors for 90-day readmissions; and (3) quantify 90-day episode-of-care health care costs.

BACKGROUND

Spinal epidural abscess (SEA), while rare, occurring ~2.5-5.1/10,000 admissions, may lead to permanent neurologic deficits and mortality. Definitive treatment often involves surgical intervention via decompression.

METHODS

A search of the PearlDiver database from 2010 to 2021 for patients undergoing decompression for SEA identified 4595 patients. Cohorts were identified through the International Classification of Disease, Ninth Revision (ICD-9), ICD-10, and Current Procedural Terminology codes. Baseline demographics of patients who were/were not readmitted within 90 days following decompression were aggregated/compared, identifying factors associated with readmission. Using Bonferroni correction, a P-value<0.001 was considered statistically significant.

RESULTS

Readmission within 90 days of surgical decompression occurred in 36.1% (1659/4595) of patients. While age/gender were not associated with readmission rate, alcohol use disorder, arrhythmia, chronic kidney disease, ischemic heart disease, and obesity were associated with readmission. Readmission risk factors included fluid/electrolyte abnormalities, obesity, paralysis, tobacco use, and pathologic weight loss (P<0.0001). Mean same-day total costs ($17,920 vs. $8204, P<0.001) and mean 90-day costs ($46,050 vs. $15,200, P<0.001) were significantly higher in the readmission group.

CONCLUSION

A substantial proportion of patients (36.1%) are readmitted within 90 days following surgical decompression for SEA. The top 5 risk factors in descending order are fluid/electrolyte abnormalities, pathologic weight loss, tobacco use, pre-existing paralysis, and obesity. This study highlights areas for perioperative medical optimization that may reduce health care utilization.

The utility of vertebral Hounsfield units as a prognostic indicator of adverse events following treatment of spinal epidural abscess

Background

Spinal epidural abscesses (SEAs) are a devastating condition with high levels of associated morbidity and mortality. Hounsfield units (HUs), a marker of radiodensity on CT scans, have previously been correlated with adverse events following spinal interventions. We evaluated whether HUs might also be associated with all-cause complications and/or mortality in this high-risk population.

Methods

This retrospective cohort study was carried out within an academic health system in the United States. Adults diagnosed with a SEA between 2006 and 2021 and who also had a CT scan characterizing their SEA within 6 months of diagnosis were considered. HUs were abstracted from the 4 vertebral bodies nearest to, but not including, the infected levels. Our primary outcome was the presence of composite 90-day complications and HUs represented the primary predictor. A multivariable logistic regression analysis was conducted adjusting for demographic and disease-specific confounders. In sensitivity testing, separate logistic regression analyses were conducted (1) in patients aged 65 and older and (2) with mortality as the primary outcome.

Results

Our cohort consisted of 399 patients. The overall incidence of 90-day complications was 61.2% (n=244), with a 7.8% (n=31) 90-day mortality rate. Those experiencing complications were more likely to have undergone surgery to treat their SEA (58.6% vs. 46.5%; p=.018) but otherwise the cohorts were similar. HUs were not associated with composite 90-day complications (Odds ratio [OR] 1.00 [95% CI 1.00-1.00]; p=.842). Similar findings were noted in sensitivity testing.

Conclusions

While HUs have previously been correlated with adverse events in certain clinical contexts, we found no evidence to suggest that HUs are associated with all-cause complications or mortality in patients with SEAs. Future research hoping to leverage 3-dimensional imaging as a prognostic measure in this patient population should focus on alternative targets.

Level of Evidence

Level III; Observational Cohort study.

Keeping It Simple: Developing a Prognostic Tool for Spinal Epidural Abscess

STUDY DESIGN

A retrospective study.

OBJECTIVE

To develop a prognostic score for mortality and treatment failure in Spinal epidural abscess (SEA), based on simplicity and multidimensional assessment principles.

METHODS

One-hundred-fifty patients were reviewed. Variables assessed included comorbidities, functional status, clinical presentation, Frankel classification, and biochemical and radiological parameters. The main outcomes were the 90-day mortality and treatment failure, corresponding to any intensification of the initial treatment plan. Variables were sorted out with a factorial analysis. Logistic regressions were performed, and the new score was derived from the coefficients. ROC curves with Area Under Curve, calibration plots, and cross-validation were performed.

RESULTS

Forty-three patients (29%) had treatment failure, and 15 died (10%) by 90 days. Factorization created 3 groups: Comorbidities (C), Severity (S), and Function (F). For 90-day mortality, Odds ratios were 1.20 (P = .0002), 1.15, (P = .03), 1.36, (P < 10-4) for C, S, F, respectively. The new score 'CSF' had 1 point per item, ranging from zero to 3. OR increased by 1.2/point for 90-day mortality (P < 10-4), AUC was .86. For failures OR increased by 1.15/point (P = .014), AUC was .58, and increased to .64 for patients who survived after 90 days, probably due to competing risks.

CONCLUSIONS

Comorbidities, Severity, and Function is a new simplistic tool, easy to use in daily practice; its performances were excellent for 90-day mortality, and acceptable for failures. Simple tools are more likely to be adopted into practice. External validation of this technique is desirable.

Preoperative Risk Factors Affecting Outcome in Surgically Treated Pyogenic Spondylodiscitis

STUDY DESIGN

Retrospective study.

OBJECTIVE

The primary aim of this study was to investigate the predictors of severe complications in patients following surgery for pyogenic spondylodiscitis (PS) using a surgeon-maintained database. The secondary aim was to investigate the predictors of early recovery.

METHODS

We introduced a surgeon-maintained database of prospectively collected multicenter data that mainly focused on perioperative complications in 2012. Our surgeon-maintained database allows the retrospective collection of detailed data. We analyzed 143 patients who underwent surgery for PS from the 19,056 patients in the prospective surgeon-maintained database at 27 affiliated institutions between 2013 and 2017. Data relating to preoperative patient factors, infection factors, surgical factors, and pre- and postoperative blood tests was retrospectively collected. We performed multivariate regression analysis to evaluate the predictors of postoperative severe complications and early recovery in patients with PS.

RESULTS

High updated Charlson comorbidity index (uCCI), chronic pulmonary disease, diabetes, Gram-negative bacteria, pyogenic osteoarthritis, high preoperative white blood cell count, and low preoperative platelet count were significantly associated with severe complications in patients undergoing surgery for PS. A high uCCI was the sole independent negative predictor on early recovery.

CONCLUSION

Careful perioperative management is necessary if surgery is performed on patients who are at a high risk of life-threatening events.

Mixed pyogenic and tuberculous spinal epidural abscesses perforating the dura and extending into the subdural space: A case report and review of the literature

Background

Spinal infections are associated with a wide variety of clinical conditions, including osteomyelitis, spondylitis, diskitis, septic facet joints, and abscesses. Based on its anatomical relationship with the dura mater, the abscess can be epidural (extradural) or subdural (intrathecal). Subdural intramedullary abscesses of the lumbar spinal canal are more common than subdural extramedullary abscesses. Here, we present a rare case of a patient with a mixed pyogenic and tuberculous epidural abscess in the lumbar spine, which perforated the dura and extended to the subdural space.

Case Description

A 29-year-old male presented with progressively worsening back pain and lower-limb weakness over a period of 3 months, with an associated inability to walk, intermittent radicular pain primarily on the left side, intermittent incontinence, and a history of low-grade fever and night sweats. The patient had a history of intravenous (IV) drug abuse and reported practicing unprotected sexual intercourse. Furthermore, the patient had recently came into contact with a person diagnosed with tuberculosis (TB). The patient was administered empirical broad-spectrum antibiotics and underwent emergent L4-L5 laminectomy and spinal abscess decompression. IV antibiotics were selected based on culture results, and anti-TB medications were started. Postoperatively, the patient demonstrated a remarkable lower-limb power improvement and radicular pain alleviation.

Conclusion

Spinal epidural abscess perforation of the dura and extension into the subdural space is extremely rare. Distinguishing between epidural and subdural abscesses radiologically is challenging. Multiple risk factors, such as unprotected sexual contact and IV drug misuse, may be associated with the development of polymicrobial abscesses in the lumbar spine. Careful anticipation, identification, and isolation of the causative micro-organisms can ensure effective antibacterial treatment. Early diagnosis, expeditious surgical decompression, and antibiotic treatment are associated with promising outcomes.

A comprehensive clinical analysis of the use of percutaneous endoscopic debridement for the treatment of early lumbar epidural abscesses

Objective

The purpose of this study is to evaluate the safety and efficacy of a percutaneous endoscopic debridement and drainage for lumbar infections with early epidural abscesses.

Methods

Eight cases of early epidural abscess underwent lumbar intervertebral space debridement and drainage by percutaneous endoscopic. Laboratory indicators, pathogenic microorganisms and complications were documented, and the ASIA scores were used to assess preoperative and postoperative neurological function changes. Additionally, the VAS was used to evaluate the therapeutic effect.

Results

The average duration of the drainage tube was 11.25 ± 3.96 days (7-20 days), and the epidural abscess was eliminated after the tube was taken out. Postoperative CRP (14.40 ± 12.50 mg/L) and ESR (48.37 ± 16.05 mm/1 h) were significantly lower than the preoperative CRP (62.5 ± 61.1 mg/L) and ESR (75.30 ± 26.20 mm/1 h). The VAS score after the operation (2.50 ± 0.92 points) was significantly lower than the one before the surgery (8.25 ± 0.83 points). 5 patients experienced lower extremity pain and neurological dysfunction prior to surgery, however, after drainage, the lower extremity pain dissipated and the lower extremity muscle strength improved in one patient. All 8 patients were followed up for a period of (28.13 ± 10.15) months, including 3 patients with spinal segmental instability who had lumbar bone graft and internal fixation for the second stage. At the end of the follow-up, all 8 patients were clinically cured without any progressive nerve injury, paraplegia or recurrence of infection.

Conclusion

Percutaneous Endoscopic Debridement and Drainage is an effective way to drain intraspinal abscesses, thus avoiding any potential progressive harm to the spinal cord.

External validation of a predictive algorithm for in-hospital and ninety-day mortality after spinal epidural abscess

BACKGROUND CONTEXT

Mortality in patients with spinal epidural abscess (SEA) remains high. Accurate prediction of patient-specific prognosis in SEA can improve patient counseling as well as guide management decisions. There are no externally validated studies predicting short-term mortality in patients with SEA.

PURPOSE

The purpose of this study was to externally validate the Skeletal Oncology Research Group (SORG) stochastic gradient boosting algorithm for prediction of in-hospital and 90-day postdischarge mortality in SEA.

STUDY DESIGN/SETTING

Retrospective, case-control study at a tertiary care academic medical center from 2003 to 2021.

PATIENT SAMPLE

Adult patients admitted for radiologically confirmed diagnosis of SEA who did not initiate treatment at an outside institution.

OUTCOME MEASURES

In-hospital and 90-day postdischarge mortality.

METHODS

We tested the SORG stochastic gradient boosting algorithm on an independent validation cohort. We assessed its performance with discrimination, calibration, decision curve analysis, and overall performance.

RESULTS

A total of 212 patients met inclusion criteria, with a short-term mortality rate of 10.4%. The area under the receiver operating characteristic curve (AUROC) of the SORG algorithm when tested on the full validation cohort was 0.82, the calibration intercept was -0.08, the calibration slope was 0.96, and the Brier score was 0.09.

CONCLUSIONS

With a contemporaneous and geographically distinct independent cohort, we report successful external validation of a machine learning algorithm for prediction of in-hospital and 90-day postdischarge mortality in SEA.

V, Prasad P, Leasure J, Stepansky F, Piple A, Kondrashov D. Pyogenic spinal infections warrant a total spine MRI

Study design: retrospective case series. Objective: the presenting clinical symptoms of spinal infections are often nonspecific and a delay in diagnosis can lead to adverse patient outcomes. The morbidity and mortality of patients with multifocal spinal infections is significantly higher compared to unifocal infections. The purpose of the current study was to analyse the risk factors for multifocal spinal infections. Methods: we conducted a retrospective review of all pyogenic non-tuberculous spinal infections treated surgically at a single tertiary care medical center from 2006-2020. The medical records, imaging studies, and laboratory data of 43 patients during this time period were reviewed and analysed after receiving Institutional Review Board approval. Univariate and multivariate analyses were performed to identify factors associated with a multifocal spinal infection. Results: 15 patients (35 %) had multifocal infections. In univariate analysis, there was a significant association with chronic kidney disease ( p = 0.040 ), gender ( p = 0.003 ), a white blood cell count ( p = 0.011 ), and cervical ( p < 0.001 ) or thoracic ( p < 0 .001) involvement. In multivariate analysis, both cervical and thoracic involvement remained statistically significant ( p = 0.001 and p < 0.001 , respectively). Conclusions: patients with infections in the thoracic or cervical region are more likely to have a multifocal infection. Multifocal pyogenic spinal infections remain a common entity and a total spine MRI should be performed to aid in prompt diagnosis.

Extensive spinal epidural abscess caused by Staphylococcus epidermidis: A case report and literature review

Background

Extensive spinal epidural abscess (SEA) is an exceptional and threatening condition that requires prompt recognition and proper management to avoid potentially disastrous complications. We aimed to find key elements of early diagnosis and rational treatments for extensive SEA.

Case presentation

A 70-year-old man complained of intense pain in the cervical-thoracic-lumbar spine that radiated to the lower extremity. Laboratory test results revealed a marked increase in all indicators of infection. The spinal magnetic resonance imaging (MRI) revealed a ventral SEA extending from C2 to L4. Owing to the patient's critical condition, laminectomy, drainage, and systemic antibiotic therapy were administered. And the multidrug-resistant Staphylococcus epidermidis was detected in the purulent material from this abscess.

Results

Postoperative MRI revealed diminished epidural abscess, and the clinical symptoms were dramatically and gradually relieved after two rounds of surgery and systemic antibiotic therapy involving the combination of ceftriaxone, linezolid, and rifampicin.

Conclusions

A comprehensive emergency assessment based on neck or back pain, neurological dysfunctions, signs of systemic infection, and MRI are important for early diagnosis of extensive SEA. Further, the combination of laminectomy, drainage, and systemic antibiotic therapy may be a rational treatment choice for patients with SEA, especially for extensive abscess or progressive neurological dysfunction.

Predictors of reoperation after surgery for spinal epidural abscess

BACKGROUND CONTEXT

Spinal epidural abscess is a rare but severe condition with high rates of postoperative adverse events.

PURPOSE

The objective of the study was to identify independent prognostic factors for reoperation using two datasets: an institutional and national database.

STUDY DESIGN/SETTING

Retrospective Review.

PATIENT SAMPLE

Database 1: Review of five medical centers from 1993 to 2016. Database 2: The National Surgical Quality Improvement Program (NSQIP) was queried between 2012 and 2016.

OUTCOME MEASURES

Thirty-day and ninety-day reoperation rate.

METHODS

Two independent datasets were reviewed to identify patients with spinal epidural abscesses undergoing spinal surgery. Multivariate analyses were used to determine independent prognostic factors for reoperation while including factors identified in bivariate analyses.

RESULTS

Overall, 642 patients underwent surgery for a spinal epidural abscess in the institutional cohort, with a 90-day unplanned reoperation rate of 19.9%. In the NSQIP database, 951 patients were identified with a 30-day unplanned reoperation rate of 12.3%. On multivariate analysis in the NSQIP database, cervical spine abscess was the only factor that reached significance for 30-day reoperation (OR=1.71, 95% CI=1.11-2.63, p=.02, Area under the curve (AUC)=0.61). On multivariate analysis in the institutional cohort, independent prognostic factors for 30-day reoperation were: preoperative urinary incontinence, ventral location of abscess relative to thecal sac, cervical abscess, preoperative wound infection, and leukocytosis (AUC=0.65). Ninety-day reoperation rate also found hypoalbuminemia as a significant predictor (AUC=0.66).

CONCLUSION

Six novel independent prognostic factors were identified for 90-day reoperation after surgery for a spinal epidural abscess. The multivariable analysis fairly predicts reoperation, indicating that there may be additional factors that need to be uncovered in future studies. The risk factors delineated in this study through the use of two large cohorts of spinal epidural abscess patients can be used to improve preoperative risk stratification and patient management.

The effect of low preoperative platelet count on adverse outcomes following lumbar microdiscectomy

Background

Low preoperative platelet count, or thrombocytopenia, has previously been associated with increased complications in elective spine surgeries. No other study has investigated the effects of abnormal coagulation profiles on postoperative outcomes specific to lumbar microdiscectomy (MLD) using a propensity matched cohort.

Methods

Patient data was retrospectively retrieved from the National Surgical Quality Improvement Program database using Current Procedural Terminology (CPT) code 63030 to isolate patients who solely underwent MLD. Data was collected from 2010 to 2019 and included preoperative, perioperative, and 30-day postoperative variables. Patients were grouped into four platelet categories for ANOVA analysis and pairwise comparisons: Severe Thrombocytopenia (≤100), Thrombocytopenia (101-150), Moderate (151-199), and Normal (200-450). Variables that were significant in the univariate analysis were used in the multivariate analysis to determine the likelihood of experiencing adverse postoperative events – unplanned return to the operating room and surgical site infection. A propensity matched analysis was performed to control for confounding variables.

Results

A total of 64,747 patients were identified within the 10-year period. The results of the multivariate analysis and the propensity matched analysis showed no significant differences in low preoperative platelet count as an independent predictor of experiencing a return to the operating room or surgical site infection. Furthermore, patients who had diabetes, history of smoking, or had emergency cases were associated with a high likelihood of experiencing these negative adverse events.

Conclusion

Thrombocytopenia does not appear to independently predict return to the operating room or postoperative infection following MLD. Proper preoperative management strategies should be implemented to monitor comorbidity burden which would otherwise influence adverse outcomes in patients with thrombocytopenia undergoing MLD.

Decompression only versus fusion in octogenarians with spinal epidural abscesses: early complications, clinical and radiological outcome with 2-year follow-up

Despite increased life expectancy due to health care quality improvements globally, pyogenic vertebral osteomyelitis (PVO) treatment with a spinal epidural abscess (SEA) remains challenging in patients older than 80 years. We aimed to assess octogenarians for PVO prevalence with SEA and compare after-surgery clinical outcomes of decompression and decompression and instrumentation. A retrospective review of electronic medical records at a single institution was conducted between September 2005 and December 2020. Patient demographics, surgical characteristics, complications, hospital course, and 90-day mortality were collected. Comorbidities were assessed using the age-adjusted Charlson comorbidity index (CCI). Over 16 years, 35 patients aged ≥80 years with PVO and SEA were identified. Eighteen patients underwent surgical decompression (“decompression group”), and 17 underwent surgical decompression with instrumentation (“instrumentation group”). Both groups had a CCI >6 (mean±SD, 8.9±2.1 vs. 9.6±2.7, respectively; p=0.065). Instrumentation group patients had a significantly longer hospital stay but no ICU stay. In-hospital and 90-days mortality rates were similar in both groups. The mean follow-up was 26.6±12.4 months. No further surgeries were performed. Infection levels and neurological status were improved in both groups at discharge. At the second-stage analysis, significant improvements in the blood infection parameters and the neurological status were detected in the decompression group. Octogenarians with PVO and SEA have a high adverse events risk after surgical procedures. Surgical decompression might contribute to earlier clinical recovery in older patients. Thus, the surgical approach should be discussed with patients and their relatives and be carefully weighed.

Symptomatic Epidural Hematoma After Elective Cervical Spine Surgery: Incidence, Timing, Risk Factors, and Associated Complications

BACKGROUND

As the rate of elective cervical spine surgery increases, studies of complications may improve quality of care. Symptomatic postoperative cervical epidural hematomas (PCEH) are rare but result in significant morbidity. Because of their low incidence, the risk factors and complications associated with symptomatic PCEH remain unclear.

OBJECTIVE

To clarify the prevalence, timing, variables, and complications associated with PCEH following elective cervical spine surgery.

METHODS

Using the American College of Surgeons National Surgical Quality Improvement Program database, cervical spine surgeries performed between 2012 and 2016 were identified using Current Procedural Terminology codes. Symptomatic PCEH was defined as readmission or reoperation events specifically associated with International Classification of Diseases code diagnoses of postoperative hematoma within 30 d of index surgery. Multivariate models were created to assess the independent association of symptomatic PCEH with other postoperative complications.

RESULTS

There were 53233 patients included for analysis. The overall incidence of symptomatic PCEH was 0.4% (n = 198). Reoperation occurred in 158 cases (78.8%), of which 2 required a second reoperation (1.3%). The majority (91.8%) of hematomas occurred within 15 d of surgery. Multivariate analysis identified male gender, American Society of Anesthesiologists classes 3 to 5, bleeding disorder, increasing number of operative levels, revision surgery, dural repair, and perioperative transfusion as independent factors associated with PCEH. Upon controlling for those confounders, PCEH was independently associated with cardiac arrest, stroke, deep vein thrombosis, surgical site infection, and pneumonia.

CONCLUSION

Postoperative epidural hematomas requiring readmission or reoperation following elective cervical spine surgery occurred at an incidence of 0.4%. Symptomatic PCEHs are associated with increased rates of numerous major morbidities.

Disseminated Spinal Epidural Abscess in an Immunocompetent Individual: A Case Report and Review of the Literature

Spinal epidural abscess (SEA) is an uncommon pyogenic infection, localized between the dura mater and vertebral periosteum, leading to significant morbidity and mortality. SEA development is connected with medical comorbidities and risk factors facilitating bacterial dissemination; multiple factors are believed to play a role, including aging, increased alcohol abuse, use of intravenous drugs, a greater prevalence of medical comorbidities, and increased rates of spinal surgery that furthers iatrogenic spinal infection. Here, we have reported the first known case of disseminated SEA in an immunocompetent individual. A 33-year-old Japanese woman visited our hospital due to 1 week of continuous fever, low back pain, and numbness of the entire left lower limb. She was diagnosed with disseminated SEA by complete spine magnetic resonance imaging scan, of unknown origin. She was treated for 13 days with piperacillin-tazobactam, then for 16 days with levofloxacin tablets; ultimately, she recovered without treatment complications. This case highlights the complicated pathology, diagnosis, and treatment of SEA. In addition, this case suggests the need for a careful and detailed examination when encountering patients presenting with fever, low back pain even in an immunocompetent individual; we should thoroughly investigate, including further image investigations, bacteriological and pathologic examination.

Antitumor necrosis factor alpha and an epidural abscess during a spinal cord stimulator trial: A case report

Spinal cord stimulation (SCS) is commonly utilized for treatment and management of chronic intractable low back and lower extremity pain. Although SCS is an overall low-risk procedure, there are potential life-threatening complications, including surgical site infections, such as an epidural abscess. Immunosuppression, a risk factor for epidural abscess, is becoming more common as an increasing number of patients are being treated with biologics for a multitude of autoimmune disorders. One class of commonly utilized biologics is antitumor necrosis factor (anti-TNF) alpha. Whereas these drugs can provide tremendous benefit for treatment and management of autoimmune disorders, there is no clear understanding of the degree to which these medications increase a patient's risk for surgical site infection, including those associated with SCS-related procedures. We present a case of an epidural abscess that developed immediately following an SCS trial in a patient with multiple undisclosed risk factors, including the use of an anti-TNF alpha agent to treat ankylosing spondylitis. For an epidural abscess, early diagnosis is key to preventing devastating complications and the need for surgical intervention. Immunosuppression can be the result of multiple issues including cancer, HIV, and biologic agents, such as anti-TNF alpha for the management of autoimmune diseases. There is limited evidence pertaining to the development of epidural abscesses in patients on anti-TNF alpha medications who undergo SCS. Studies focused on infections in patients undergoing SCS trials and permanent implants while on anti-TNF alpha agents could provide recommendations and guidance.

Spinal Epidural Abscess: Diagnosis, Management, and Outcomes

An infection of the spinal epidural space, spinal epidural abscess (SEA) is a potentially devastating entity that is rising in incidence. Its insidious presentation, variable progression, and potential for precipitous neurologic decline make diagnosis and management of SEA challenging. Prompt diagnosis is key because treatment delay can lead to paralysis or death. Owing to the nonspecific symptoms and signs of SEA, misdiagnosis is alarmingly common. Risk factor assessment to determine the need for definitive MRI reduces diagnostic delays compared with relying on clinical or laboratory findings alone. Although decompression has long been considered the benchmark for SEA, considerable risk associated with spinal surgery is noted in an older cohort with multiple comorbidities. Nonoperative management may represent an alternative in select cases. Failure of nonoperative management is a feared outcome associated with motor deterioration and poor clinical outcomes. Recent studies have identified independent predictors of failure and residual neurologic dysfunction, recurrence, and mortality. Importantly, these studies provide tools that generate probabilities of these outcomes. Future directions of investigation should include external validation of existing algorithms through multi-institutional collaboration, prospective trials, and incorporation of powerful predictive statistics such as machine learning methods.

Evaluating new paralysis, mortality, and readmission among subgroups of patients with spinal epidural abscess: A latent class analysis

Background

Spinal epidural abscess (SEA) is increasing in incidence; this not-to-miss diagnosis can cause significant morbidity and mortality, particularly if diagnoses are delayed. While some risk factors for SEA and subsequent mortality have been identified, the SEA patient population is clinically heterogeneous and sub-populations have not yet been characterized in the literature. The primary objective of this project was to identify characteristics of subgroups of patients with SEA. The secondary objective was to identify associations between subgroups and three clinical outcomes: new onset paralysis, in-hospital mortality, and 180-day readmission.

Methods

Demographics and comorbid diagnoses were collected for patients diagnosed with SEA at an academic health center between 2015 and 2019. Latent class analysis was used to identify clinical subgroups. Chi-squared tests were used to compare identified subgroups with clinical outcomes.

Results

We identified two subgroups of patients in our analysis. Group 1 had a high rate of medical comorbidities causing immunosuppression, requiring vascular access, or both. Group 2 was characterized by a high proportion of people with substance use disorders. Patients in Group 2 were more likely to be readmitted within 6 months than patients in Group 1 (p = 0.03). There was no difference between groups in new paralysis or mortality.

Discussion

While prior studies have examined the SEA patient population as a whole, our research indicates that there are at least two distinct subgroups of patients with SEA. Patients who are younger, with substance use disorder diagnoses, may have longer hospital courses and are at higher risk of readmission within six months. Future research should explore how to best support patients in both groups, and additional implications for subgroup classification on health outcomes, including engagement in care.

Evaluation of Predictive Models for Complications following Spinal Surgery

BACKGROUND

 Complications rates vary across spinal surgery procedures and are difficult to predict due to heterogeneity in patient characteristics, surgical methods, and hospital volume. Incorporation of predictive models for complications may guide surgeon decision making and improve outcomes.

METHODS

 We evaluate current independently validated predictive models for complications in spinal surgery with respect to study design and model generation, accuracy, reliability, and utility. We conducted our search using Preferred Reporting Items for Systematic Review and Meta-analysis guidelines and the Participants, Intervention, Comparison, Outcomes, Study Design model through the PubMed and Ovid Medline databases.

RESULTS

 A total of 18 articles met inclusion criteria including 30 validated predictive models of complications after adult spinal surgery. National registry databases were used in 12 studies. Validation cohorts were used in seven studies for verification; three studies used other methods including random sample bootstrapping techniques or cross-validation. Reported area under the curve (AUC) values ranged from 0.37 to 1.0. Studies described treatment for deformity, degenerative conditions, inclusive spinal surgery (neoplasm, trauma, infection, deformity, degenerative), and miscellaneous (disk herniation, spinal epidural abscess). The most commonly cited risk factors for complications included in predictive models included age, body mass index, diabetes, sex, and smoking. Those models in the deformity subset that included radiographic and anatomical grading features reported higher AUC values than those that included patient demographics or medical comorbidities alone.

CONCLUSIONS

 We identified a cohort of 30 validated predictive models of complications following spinal surgery for degenerative conditions, deformity, infection, and trauma. Accurate evidence-based predictive models may enhance shared decision making, improve rehabilitation, reduce adverse events, and inform best practices.

The Prognostic Value of Laboratory Markers and Ambulatory Function at Presentation for Post-Treatment Morbidity and Mortality Following Epidural Abscess

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To develop a comprehensive understanding of the prognostic value of laboratory markers on morbidity and mortality following epidural abscess.

SUMMARY OF BACKGROUND DATA

Spinal epidural abscess is a serious medical condition with high rates of morbidity. The value of laboratory data in forecasting morbidity and mortality after epidural abscess remains underexplored.

METHODS

We obtained clinical data on patients treated for epidural abscess at two academic centers from 2005 to 2017. Our primary outcome was the development of one or more complications within 90-days of presentation, with mortality a secondary measure. Primary predictors included serum albumin, serum creatinine, platelet-lymphocyte ratio, and ambulatory status at presentation. We used multivariable logistic regression techniques to adjust for confounders. The most parsimonious set of variables influencing both complications and mortality were considered to be clinically significant. These were then examined individually and in combination to assess for synergy along with model-discrimination and calibration. We performed internal validation with a bootstrap procedure using sampling with replacement.

RESULTS

We included 449 patients in this analysis. Complications were encountered in 164 cases (37%). Mortality within 1-year occurred in 39 patients (9%). Regression testing determined that serum albumin, serum creatinine, and ambulatory status at presentation were clinically important predictors of outcome, with albumin more than 3.5 g/dL, creatinine less than or equal to 1.2 mg/dL, and independent ambulatory function at presentation considered favorable characteristics. Patients with no favorable findings had increased likelihood of 90-day complications (odds ratio [OR] 5.43; 95% confidence intervals [CI] 1.98, 14.93) and 1-year mortality (OR 8.94; 95% CI 2.03, 39.37). Those with one favorable characteristic had greater odds of complications (OR 4.00; 95% CI 2.05, 7.81) and mortality (OR 5.71; 95% CI 1.60, 20.43).

CONCLUSION

We developed a nomogram incorporating clinical and laboratory values to prognosticate outcomes after treatment for epidural abscess. The results can be used in shared-decision making and counseling.

LEVEL OF EVIDENCE

3.

Spinal Epidural Abscess: A Review of Presentation, Management, and Medicolegal Implications

Spinal epidural abscess (SEA) is a rare condition associated with significant morbidity and mortality. Despite advances in diagnostic medicine, early recognition of SEAs remains elusive. The vague presentation of the disease, coupled with its numerous risk factors, the diagnostic requirement for obtaining advanced imaging, and the necessity of specialized care constitute extraordinary challenges to both diagnosis and treatment of SEA. Once diagnosed, SEAs require urgent or emergent medical and/or surgical management. As SEAs are a relatively rare pathology, high-quality data are limited and there is no consensus on their optimal management. This paper focuses on presenting the treatment modalities that have been successful in the management of SEAs and providing a critical assessment of how specific SEA characteristics may render one infection more amenable to primary surgical or medical interventions. This paper reviews the relevant history, epidemiology, clinical presentation, radiology, microbiology, and treatment of SEAs and concludes by addressing the medicolegal implications of delayed treatment of the disease.

Risk factors for in-hospital mortality after spine surgery: a matched case-control study using a multicenter database

BACKGROUND/CONTEXT

It is yet unclear what preoperative and intraoperative factors affect mortality after spine surgery.

PURPOSE

To identify the preoperative and intraoperative risk factors for in-hospital mortality after spine surgery using a matched case-control study based on a multicenter database.

STUDY DESIGN/SETTING

A retrospective matched case-control study based on a registry of prospectively collected multicenter data.

PATIENT SAMPLE

We identified 25 patients who died in the hospital (the mortality group) from the 26,604 patients in the database who underwent spine surgery at our 27 affiliated institutions between 2012 and 2018. An age-, sex-, spinal disease-, and surgical procedure-matched control group of patients (n=100, 4:1 ratio with the mortality group) was selected from the same database.

OUTCOME MEASURES

Data relating to comorbidities, preoperative blood tests, operative factors, and perioperative complications.

METHODS

We retrospectively reviewed all the medical records of each patient in the two groups to nullify the effects of overt risk factors such as age, sex, diseases, and surgical procedures. Risk factors for in-hospital mortality were initially evaluated by univariate analysis. Then, multivariate logistic regression models were generated to analyze independent risk factors for in-hospital mortality.

RESULTS

The overall in-hospital mortality rate was 0.09% (25/26,604). Mortality was lowest in patients with degenerative cervical (0.04%, 2/5,027) or lumbar disease (0.03%, 5/15,630). In contrast, mortality was highest in patients with dialysis-related spondyloarthropathy (3.0%, 3/99), patients with infectious spondylodiscitis (1.5%, 6/401), and patients with metastatic spinal tumors (0.9%, 3/334). Multivariate logistic regression analysis revealed that massive intraoperative hemorrhage (>2 L) (odds ratio [OR], 28.2; 95% confidence interval [CI], 2.27-349), preoperative renal comorbidity (OR, 4.33; 95% CI, 1.38-13.6), and elevated preoperative aspartate aminotransferase levels (OR, 1.51 per 10 units; 95% CI, 1.04-2.20) were risk factors.

CONCLUSIONS

Spine surgery for patients with dialysis-dependency, infectious diseases or metastatic tumors had much more potential of in-hospital mortality compared with those for patients with degenerative diseases. Massive intraoperative hemorrhage and preoperative renal and liver comorbidities were identified as risk factors for in-hospital mortality in patients who underwent spine surgery.

Development of machine learning algorithms for prediction of mortality in spinal epidural abscess

BACKGROUND CONTEXT

In-hospital and short-term mortality in patients with spinal epidural abscess (SEA) remains unacceptably high despite diagnostic and therapeutic advancements. Forecasting this potentially avoidable consequence at the time of admission could improve patient management and counseling. Few studies exist to meet this need, and none have explored methodologies such as machine learning.

PURPOSE

The purpose of this study was to develop machine learning algorithms for prediction of in-hospital and 90-day postdischarge mortality in SEA.

STUDY DESIGN/SETTING

Retrospective, case-control study at two academic medical centers and three community hospitals from 1993 to 2016.

PATIENTS SAMPLE

Adult patients with an inpatient admission for radiologically confirmed diagnosis of SEA.

OUTCOME MEASURES

In-hospital and 90-day postdischarge mortality.

METHODS

Five machine learning algorithms (elastic-net penalized logistic regression, random forest, stochastic gradient boosting, neural network, and support vector machine) were developed and assessed by discrimination, calibration, overall performance, and decision curve analysis.

RESULTS

Overall, 1,053 SEA patients were identified in the study, with 134 (12.7%) experiencing in-hospital or 90-day postdischarge mortality. The stochastic gradient boosting model achieved the best performance across discrimination, c-statistic=0.89, calibration, and decision curve analysis. The variables used for prediction of 90-day mortality, ranked by importance, were age, albumin, platelet count, neutrophil to lymphocyte ratio, hemodialysis, active malignancy, and diabetes. The final algorithm was incorporated into a web application available here: https://sorg-apps.shinyapps.io/seamortality/.

CONCLUSIONS

Machine learning algorithms show promise on internal validation for prediction of 90-day mortality in SEA. Future studies are needed to externally validate these algorithms in independent populations.