Predictors of Readmissions and Reoperations Related to Venous Thromboembolic Events After Spine Surgery: A Single-Institution Experience with 6869 Patients

doi:10.1016/j.wneu.2017.11.168

World Neurosurgery

Volume 111, March 2018, Pages e91-e97

https://doi.org/10.1016/j.wneu.2017.11.168 Get rights and content

Background

Readmission and reoperation are used as hospital and surgeon quality metrics. Venous thromboembolic (VTE) events, including deep vein thrombosis and pulmonary embolism (PE), are a major cause of readmission, morbidity, and mortality after spine surgery. Specific procedural, perioperative, and patient characteristics may be associated with these outcomes.

Methods

We retrospectively examined records from 6869 consecutive spine surgeries at our institution. We collected data on patient demographics, surgery, hospital course, and 30-day rates of VTE, readmission, reoperation, and epidural hematoma. Stepwise multivariable logistic regression was used to identify independent predictors of each outcome.

Results

Factors associated with VTE within 30 days of surgery include a history of VTE (odds ratio [OR] 3.92 [confidence interval 1.83–8.36], P < 0.001), estimated blood loss (EBL; OR 1.017 [1.005–1.029], P = 0.004), fracture (OR 5.42 [2.09–14.05], P = 0.001), history of PE (OR 4.04 [1.22–13.42], P = 0.023), and transfusion (OR 2.26 [1.07–4.77], P = 0.033). Factors associated with readmission were a history of PE (OR 3.27 [1.07–9.97], P = 0.038), PE (OR 8.07 [2.26–28.8], P = 0.001), transfusion (OR 2.54 [1.55–4.17], P < 0.001), comorbid disease burden (OR 1.35 [1.01–1.80], P = 0.041), and tumor surgery (OR 2.84 [1.32–6.10], P = 0.007). Factors associated with reoperation were EBL (OR 1.024 [1.006–1.042], P = 0.008), transfusion (OR 3.86 [1.38–10.79], P = 0.01), and PE (OR 6.05 [1.03–35.62], P = 0.046). Transfusion was associated with epidural hematoma within 30 days (OR 7.38 [1.37–39.83], P = 0.02).

Conclusions

Transfusion and EBL are associated with numerous negative outcomes. Transfusion is an independent predictor of VTE, readmission, reoperation, and epidural hematoma requiring evacuation. Specific pathologies were associated with specific negative outcomes.

Introduction

Unplanned readmissions and reoperations are costly, with Medicare spending about $17 billion annually on avoidable readmissions.1, 2 The Medicare Payment Advisory Commission recommends 30-day readmission rates be public, allowing the data to be used to compare hospitals.3, 4 The Medicare Hospital Readmission Reduction Program and Bundled Payments for Care Improvement Initiative may even reduce payments and deny reimbursements to hospitals with relatively high rates of readmissions and reoperations.3, 4, 5, 6 Predicting and preventing readmission and reoperations after spine surgery is therefore a clinical priority.

Over the past few decades, the number of spine surgeries performed in the United States has increased,⁷ as has the rate of readmission and reoperation after spine surgery with an estimated 30-day readmission rate between 4.2% and 7.4%.⁸ One of the recognized and preventable cause of readmission, morbidity, and mortality after spine surgery is venous thromboembolic (VTE) events, including both deep vein thrombosis (DVT) and pulmonary embolisms (PE). A recent meta-analysis estimates that the prevalence of clinically significant VTE events after spine surgery ranges from 0.29% to 31% depending on the VTE screening methods.⁹

The goal of this study is to identify risk factors that independently predict readmissions, reoperations, and complications as a result of VTE event after spine surgery. Our aim is to better delineate subgroups of patients that would benefit from more aggressive chemoprophylaxis after spine surgery and to establish a clinically relevant 30-day readmission and reoperation rate after all spine surgeries at a single institution.

Section snippets

Data Source

A total of 6869 patients who underwent spine surgery by 35 spine surgeons in the Department of Neurological Surgery or Orthopaedic Surgery at Northwestern Memorial Hospital between January 1, 2009, and May 31, 2015, were identified with the Northwestern University Electronic Data Warehouse (EDW). The EDW is a clinical data repository jointly funded by Northwestern Memorial Hospital, Northwestern Medical Faculty Foundation, and Northwestern University Feinberg School of Medicine. Spine surgeries

Baseline Patient Characteristics

A total of 6869 procedures met the study inclusion criteria. The characteristics of the patients and procedures are summarized in Table 2. On average, patients undergoing spine surgery were 54.03 years old (SD 15.57) with a BMI of 28.45 (SD 6.24). More than one half of the patients were male (54%, n = 3676), white (69%, n = 4755), and reported no history of smoking (84%, n = 5780). About 3.1% (n = 215) of the patients had a history of VTE, 0.09% (n = 2) had a history of epidural hematoma, 2.7% (

Discussion

Quality improvement metrics have created interest in recognizing the causes and predictors of early readmission and reoperations,3, 4, 5, 6 as well as the complications that precipitate them. The number and complexity of spinal procedures performed annually has risen, resulting in a parallel increase in readmissions, reoperations, and complications that can be prevented or minimized.⁷ Here, we present a single-center study of 6869 consecutive procedures and identified predictors of VTE,

Conclusions

Transfusion and EBL are independent predictors of VTE events, specifically PE, after spine surgery. These VTE events are associated with numerous negative outcomes after spine surgery, including readmission and reoperation within 30 days.

References (39)

S.R. Manoharan et al.
Thirty-day readmissions following adult spinal deformity surgery: an analysis of the National Surgical Quality Improvement Program (NSQIP) database
Spine J
(2016)
M.C. Wang et al.
Thirty-day readmissions after elective spine surgery for degenerative conditions among US Medicare beneficiaries
Spine J
(2012)
S. Kukreja et al.
Predictors of reoperation-free survival following decompression-alone lumbar spine surgery for on-the-job injuries
Clin Neurol Neurosurg
(2015)
S. Sato et al.
Reoperation rate and risk factors of elective spinal surgery for degenerative spondylolisthesis: minimum 5-year follow-up
Spine J
(2015)
L. Leon et al.
The prophylactic use of inferior vena cava filters in patients undergoing high-risk spinal surgery
Ann Vasc Surg
(2005)
T.Y. Wang et al.
Independent predictors of 30-day perioperative deep vein thrombosis in 1346 consecutive patients after spine surgery
World Neurosurg
(2015)
C. Clement et al.
Incidence, risk profile and morphological pattern of lower extremity venous thromboembolism after urological cancer surgery
J Urol
(2011)
K.M. Murray et al.
Venous thromboembolism after radical cystectomy: experience with screening ultrasonography
Arab J Urol
(2016)
S.F. Jencks et al.
Rehospitalizations among patients in the Medicare fee-for-service program
N Engl J Med
(2009)
MEDPAC
Report to the Congress: Reforming the Delivery System
(2008)

A.M. Epstein

Revisiting readmissions—changing the incentives for shared accountability

N Engl J Med

(2009)

S. Guterman et al.

Using Medicare payment policy to transform the health system: a framework for improving performance

Health Aff (Millwood)

(2009)

D.R. Delisle

Big things come in bundled packages: implications of bundled payment systems in health care reimbursement reform

Am J Med Qual

(2013)

K.E. Joynt et al.

Thirty-day readmission rates for Medicare beneficiaries by race and site of care

JAMA

(2011)

J.N. Weinstein et al.

United States' trends and regional variations in lumbar spine surgery: 1992–2003

Spine (Phila Pa 1976)

(2006)

J.T. Bernatz et al.

Thirty-day readmission rates in spine surgery: systematic review and meta-analysis

Neurosurg Focus

(2015)

M.P. Glotzbecker et al.

Postoperative spinal epidural hematoma: a systematic review

Spine (Phila Pa 1976)

(2010)

B.D. Kim et al.

Predictors of unplanned readmission in patients undergoing lumbar decompression: multi-institutional analysis of 7016 patients

J Neurosurg Spine

(2014)

Centers for Medicare, Medicaid Services HHS

Medicare Program; Hospital Inpatient Prospective Payment Systems for Acute Care Hospitals and the Long-Term Care Hospital Prospective Payment System and Policy Changes and Fiscal Year 2017 Rates; Quality Reporting Requirements for Specific Providers; Graduate Medical Education; Hospital Notification Procedures Applicable to Beneficiaries Receiving Observation Services; Technical Changes Relating to Costs to Organizations and Medicare Cost Reports; Finalization of Interim Final Rules With Comment Period on LTCH PPS Payments for Severe Wounds, Modifications of Limitations on Redesignation by the Medicare Geographic Classification Review Board, and Extensions of Payments to MDHs and Low-Volume Hospitals. Final rule

Fed Regist

(2016)

Cited by (12)

Is it safe for the spinal metastasis patients with preoperative deep vein thrombosis to use low-molecular-weight heparin before surgery? A prospective study
2023, Journal of Clinical Neuroscience
Spine surgeons should weigh the risks of anticoagulants against their benefits in preventing deep venous thrombosis (DVT), as they may increase the risk of bleeding. Spinal metastasis patients undergoing decompression with fixation are at a high risk for DVT, which may occur preoperatively. Therefore, anticoagulants should be administered preoperatively. This study aimed to evaluate the safety of the administration of anticoagulants in treating spinal metastasis patients with preoperative DVT. Therefore, we prospectively investigated the prevalence of DVT in these patients. Patients who were diagnosed with preoperative DVT were included in an anticoagulant group. Subcutaneous low-molecular-weight heparin (LMWH) was administered. Patients without DVT were included in a non-anticoagulant group. Data on patient information, clinical parameters, blood test results, and bleeding complications were also collected. Moreover, the safety of anticoagulants was analyzed. The prevalence of preoperative DVT was 8.0%. None of the patients developed pulmonary thromboembolism. Furthermore, no significant differences in blood loss, drainage volume, hemoglobin levels, number of transfusions, or preoperative trans-catheter arterial embolization were observed between the two groups. None of the patients developed major bleeding. However, two patients experienced wound hematoma and one experienced incisional bleeding in the non-anticoagulant group. Therefore, LMWH is safe for spinal metastasis patients. Future randomized controlled trials should be conducted to evaluate the validity of perioperative prophylactic anticoagulation therapy in these patients.
Anterior approach lumbar fusions cause a marked increase in thromboembolic events: Causal inferences from a propensity-matched analysis of 1147 patients
2022, Clinical Neurology and Neurosurgery
Citation Excerpt :
Patients undergoing transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody fusion could be included in the posterior approach group. Given prior analyses indicating that fractures are independently associated with VTE, and that spinal neoplastic processes are associated with an elevated thromboembolic risk, we excluded patients with spinal fractures or spinal tumors from our analysis [16–20]. Patients undergoing surgery for infectious indications were also excluded.
Anterior lumbar fusions are thought to be associated with elevated venous thromboembolic event (VTE) rates, but the magnitude of this increase in VTE is not well described. The objective of this study was to quantify any increase in VTE caused by anterior approach lumbar fusion.
1147 consecutive lumbar fusions performed at our institution over a six-year period were identified, and clinical and demographic data were collected. K-nearest neighbor propensity score matching and propensity score adjusted regression were performed. Patients undergoing anterior versus posterior approach lumbar fusions were matched according to age, body mass index, sex, VTE history, estimated blood loss, length of surgery, transfusion, selection for postoperative intensive care unit (ICU) admission, comorbid disease burden, and use of chemoprophylactic anticoagulation.
Anterior approach surgery (OR=4.29, p < 0.001), a history of VTE (OR=8.67, p < 0.001), age (OR=1.53, p = 0.014), length of surgery (OR=1.16, p = 0.044), and selection for postoperative ICU admission (OR=4.60, p = 0.005) were independently associated with VTE on multivariable regression. 1058 anterior or posterior approach fusion patients were matched. After matching, overall bias was reduced by 71.0 %, no covariates remained significantly different between groups, and propensity scores were well balanced between populations (Rubin’s B≤0.25, 0.5 ≤Rubin’s R≤2.0). Significantly more patients in the anterior group underwent lower extremity duplex ultrasonography (LED) (36.9 % vs. 14.8 %, OR=3.36 [2.38, 4.76], p < 0.0001), and a statistically insignificantly higher proportion of LEDs were positive among patients in the anterior group (23.2 % vs. 13.2 %, OR=1.99 [0.92, 4.25], p = 0.108). After matching, the rate of VTE was 8.6 % for the anterior group and 1.3 % for the posterior group, with anterior approach surgery causing an increase in VTE by 7.2 % (95 % CI [2.28 %, 12.16 %], p = 0.004).
Among patients undergoing lumbar fusions, anterior approach surgery causes an increase in VTE by 7.2%, which is a multifold increase in the proportion of patients with thromboembolic complications.
Comparison of inpatient versus post-discharge venous thromboembolic events after spinal surgery: A single institution series of 6869 consecutive patients
2020, Clinical Neurology and Neurosurgery
Citation Excerpt :
Notably, inpatient DVT is not associated with readmission within 30 days, presumably because they are addressed prior to discharge. The 30-day readmission and VTE window investigated is consistent with previous published results that investigated post-discharge VTE for hospital admissions and procedures in a variety of surgical and non-surgical fields and found that even with 90-day follow up, the vast majority of VTE occur in the first 30 days post-discharge [24–28,30–34,40,41,44]. This finding suggests that anticoagulation after VTE may reduce readmission.
retrospective chart review.
We aimed to determine the perioperative risk factors that lead to inpatient or post-discharge venous thromboembolism (VTE) events after spinal surgery.
While many studies relate the risk factors in a post-surgical setting to the incidence of VTE, this study aims to separate these VTE into inpatient and post-discharge categories to examine timing and risk factors.
We analyzed 6869 patients from 2009 to 2015 using Current Procedural Technology codes from a single tertiary academic institution. Patients were stratified based on occurrence and setting of VTE then controlled for perioperative characteristics with exclusion criteria being patients undergoing minor spine surgeries or secondary procedures.
In 170 VTE events, these factors were associated with increased risk for: Inpatient DVT only: IVC filter (OR 6.380 [3.414−11.924]), longer length of hospital stay (OR 1.083 [1.047−1.120]), a prior history of DVT (OR 3.640 [1.931−6.856]). Post-discharge DVT only: history of PE (OR 45.142 [6.785−300.351]), having a corpectomy (OR 26.670 [3.477−204.548]), and having an osteotomy (OR 18.877 [1.129−315.534]). Inpatient PE only: surgery >4 h (OR 30.820, p < 0.001), fracture (OR 6.913, p = 0.004), IVC filter (OR 3.135, p = 0.029). Post-discharge PE only: corpectomy (OR 541.271, p = 0.009), foraminotomy (OR 40.137, p = 0.013), EBL > 500cc (OR 2467.798, p = 0.002). Time to onset of VTE events was significantly longer for patients undergoing osteotomy (7.43 days) than for patients with fracture (4.28 days), which is consistent with our findings that fracture was an independent predictor of inpatient VTE, and osteotomy was an independent predictor of post-discharge VTE (p = 0.018).
Time-to-VTE varies between types of surgeries. Some risk factors are independently associated with VTE at all times during the 30-day postoperative period, while other factors are only associated with either inpatient or post-discharge VTE. Those patients with high-risk features for post-discharge VTE merit increased study for thromboprophylaxis management.
Trend of unplanned reoperation rates after lumbar degenerative surgery from 2011 to 2019: a large patient population study
2023, ANZ Journal of Surgery
Chemoprophylactic Anticoagulation Following Lumbar Surgery Significantly Reduces Thromboembolic Events After Instrumented Fusions, Not Decompressions
2023, Spine
Dose-dependent effects of red blood cell transfusion and case mix index on venous thromboembolic events in spine surgery
2023, Vox Sanguinis

View all citing articles on Scopus

: Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

View full text

Original ArticlePredictors of Readmissions and Reoperations Related to Venous Thromboembolic Events After Spine Surgery: A Single-Institution Experience with 6869 Patients

Background

Methods

Results

Conclusions

Introduction

Section snippets

Data Source

Baseline Patient Characteristics

Discussion

Conclusions

Spine J

Spine J

Clin Neurol Neurosurg

Spine J

Ann Vasc Surg

World Neurosurg

J Urol

Arab J Urol

Rehospitalizations among patients in the Medicare fee-for-service program

N Engl J Med

Report to the Congress: Reforming the Delivery System

Revisiting readmissions—changing the incentives for shared accountability

N Engl J Med

Using Medicare payment policy to transform the health system: a framework for improving performance

Health Aff (Millwood)

Big things come in bundled packages: implications of bundled payment systems in health care reimbursement reform

Am J Med Qual

Thirty-day readmission rates for Medicare beneficiaries by race and site of care

JAMA

United States' trends and regional variations in lumbar spine surgery: 1992–2003

Spine (Phila Pa 1976)

Thirty-day readmission rates in spine surgery: systematic review and meta-analysis

Neurosurg Focus

Postoperative spinal epidural hematoma: a systematic review

Spine (Phila Pa 1976)

Predictors of unplanned readmission in patients undergoing lumbar decompression: multi-institutional analysis of 7016 patients

J Neurosurg Spine

Fed Regist

Original Article
Predictors of Readmissions and Reoperations Related to Venous Thromboembolic Events After Spine Surgery: A Single-Institution Experience with 6869 Patients