Prevalence and risk factors of deep vein thrombosis in patients undergoing lumbar spine surgery

Venous thromboembolism prophylaxis and mortality in patients with spinal fractures in ICUs

BACKGROUND

Spinal fracture is a common traumatic condition in orthopaedics, accounting for 5%-6% of total body fractures, and is a high-risk factor for venous thromboembolism (VTE), which seriously affects patient prognosis.

AIM

The aim of this study was to determine the impact of VTE prophylaxis on the prognosis of patients with spinal fractures in intensive care units (ICUs) and to provide a scientific basis for clinical treatment and nursing.

DESIGN

A retrospective study of patients with spinal fractures from the multicenter eICU Collaborative Research Database.

METHOD

The outcomes of this study were ICU mortality and in-hospital mortality. Patients were divided into the VTE prophylaxis (VP) and no VTE prophylaxis (NVP) groups according to whether they had undergone VTE prophylaxis during their ICU admission. The association between groups and outcomes were analysed using Kaplan-Meier (KM) survival curve, log-rank test and the Cox proportional-hazards regression model.

RESULTS

This study included 1146 patients with spinal fractures: 330 in the VP group and 816 in the NVP group. KM survival curves and log-rank tests revealed that both ICU and in-hospital survival probabilities in the VP group were significantly higher than in the NVP group. After the Cox model was adjusted for all covariates, the hazard ratio for ICU mortality in the VP group was 0.38 (0.19-0.75); the corresponding value for in-hospital mortality in the VP group was 0.38 (0.21-0.68).

CONCLUSIONS

VTE prophylaxis is associated with reduced ICU and in-hospital mortality in patients with spinal fractures in ICUs. More research is necessary to further define specific strategies and optimal timing for VTE prophylaxis.

RELEVANCE TO CLINICAL PRACTICE

This study provides the basis that VTE prophylaxis may be associated with improved prognosis in patients with spinal fractures in ICUs. In clinical practice, an appropriate modality should be selected for VTE prophylaxis in such patients.

Does the choice of chemoprophylaxis affect the prevention of deep vein thrombosis in lumbar fusion surgery? A systematic review of the literature

Introduction

To date, the available guidance on venous thromboembolism (VTE) prevention in elective lumbar fusion surgery is largely open to surgeon interpretation and preference without any specific suggested chemoprophylactic regimen.

Research question

This study aimed to comparatively analyze the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) with the use of commonly employed chemoprophylactic agents such as unfractionated heparin (UH) and low molecular weight heparin (LMWH) in lumbar fusion surgery.

Material and methods

An independent systematic review of four scientific databases (PubMed, Scopus, clinicaltrials.gov, Web of Science) was performed to identify relevant articles as per the preferred reporting in systematic reviews and meta-analysis (PRISMA) guidelines. Studies reporting on DVT/PE outcomes of lumbar fusion surgery in adult patients with UH or LMWH chemoprophylaxis were included for analysis. Analysis was performed using the Stata software.

Results

Twelve studies with 8495 patients were included in the analysis. A single-arm meta-analysis of the included studies found a DVT incidence of 14% (95%CI [8%-20%]) and 1% (95%CI [-6% - 8%]) with LMWH and UH respectively. Both the chemoprophylaxis agents prevented PE with a noted incidence of 0% (95%CI [0%-0.1%]) and 0% (95%CI [0%-1%]) with LMWH and UH respectively. The risk of bleeding-related complications with the usage of LMWH and UH was 0% (95% CI [0.0%-0.30%]) and 3% (95% CI [0.3%-5%]) respectively.

Discussion and conclusion

Both LMWH and UH reduces the overall incidence of DVT/PE, but there is a paucity of evidence analyzing the comparative effectiveness of the chemoprophylaxis regimens in lumbar fusion procedures. The heterogeneity in data prevents any conclusions, as there remains an evidence gap. We recommend future high-quality randomized controlled trials to investigate in this regard to help develop recommendations on thromboprophylaxis usage.

Venous Thromboembolism Rates Have Not Decreased in Elective Lumbar Fusion Surgery from 2011 to 2020

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

This study aimed to (1) evaluate for any temporal trends in the rates of VTE, deep venous thrombosis (DVT), pulmonary embolism (PE), and mortality from 2011 to 2020 and (2) identify the predictors of VTE following lumbar fusion surgery.

METHODS

Annual incidences of 30-day VTE, DVT, PE, and mortality were calculated for each of the operation year groups from 2011 to 2020. Multivariable Poisson regression was utilized to test the association between operation year and primary outcomes, as well as to identify significant predictors of VTE.

RESULTS

A total of 121,205 patients were included. There were no statistically significant differences in VTE, DVT, PE, or mortality rates among the operation year groups. Multivariable regression analysis revealed that compared to 2011, operation year 2019 was associated with significantly lower rates of DVT. Age, BMI, prolonged operation time, prolonged length of stay, non-home discharge, anterior fusion, smoking status, functional dependence, and chronic steroid use were identified as independent predictors of VTE following lumbar fusion. Female sex, Hispanic ethnicity, and outpatient surgery setting were identified as protective factors from VTE in this cohort.

CONCLUSIONS

Rates of VTE after lumbar fusion have remained mostly unchanged between 2011 and 2020. Older age, higher BMI, longer operation time, prolonged length of stay, non-home discharge, anterior fusion, smoking, functional dependence, and steroid use were independent predictors of VTE after lumbar fusion, while female sex, Hispanic ethnicity, and outpatient surgery were the protective factors.

Risk factors for venous thromboembolism following surgical treatment of fractures: A systematic review and meta-analysis

This study aimed to determine the risk factors for postoperative venous thromboembolism (VTE) in patients treated surgically for fractures using a meta-analytic approach. Electronic searches were performed in PubMed, Embase, and the Cochrane library from inception until February 2022. The odds ratio (OR) and 95% confidence interval (CI) were applied to calculate the pooled effect estimate using the random-effects model. Sensitivity, subgroup, and publication bias tests were also performed. Forty-four studies involving 3 239 291 patients and reporting 11 768 VTE cases were selected for the meta-analysis. We found that elderly (OR: 1.72; 95% CI: 1.38-2.15; P < .001), American Society of Anesthesiologists (ASA) ≥ 3 (OR: 1.82; 95% CI: 1.46-2.29; P < .001), blood transfusion (OR: 1.82; 95% CI: 1.14-2.92; P = .013), cardiovascular disease (CVD) (OR: 1.40; 95% CI: 1.22-1.61; P < .001), elevated D-dimer (OR: 4.55; 95% CI: 2.08-9.98; P < .001), diabetes mellitus (DM) (OR: 1.36; 95% CI: 1.19-1.54; P < .001), hypertension (OR: 1.31; 95% CI: 1.09-1.56; P = .003), immobility (OR: 3.45; 95% CI: 2.23-5.32; P < .001), lung disease (LD) (OR: 2.40; 95% CI: 1.29-4.47; P = .006), obesity (OR: 1.52; 95% CI: 1.27-1.82; P < .001), peripheral artery disease (PAD) (OR: 2.13; 95% CI: 1.21-3.73; P = .008), prior thromboembolic event (PTE) (OR: 5.17; 95% CI: 3.14-8.50; P < .001), and steroid use (OR: 2.37; 95% CI: 1.73-3.24; P < .001) were associated with an increased risk of VTE. Additionally, regional anaesthesia (OR: 0.66; 95% CI: 0.45-0.96; P = .029) was associated with a reduced risk of VTE following surgical treatment of fractures. However, alcohol intake, cancer, current smoking, deep surgical site infection, fusion surgery, heart failure, hypercholesterolemia, liver and kidney disease, sex, open fracture, operative time, preoperative anticoagulant use, rheumatoid arthritis, and stroke were not associated with the risk of VTE. Post-surgical risk factors for VTE include elderly, ASA ≥ 3, blood transfusion, CVD, elevated D-dimer, DM, hypertension, immobility, LD, obesity, PAD, PTE, and steroid use.

Incidental Durotomy After Posterior Lumbar Decompression Surgery Associated With Increased Risk for Venous Thromboembolism

INTRODUCTION

Incidental durotomies can occur during posterior lumbar decompression surgery. Not only can this slow patient recovery but many surgeons recommend a period of bed rest in these situations, which can further slow mobilization. This immobility might be associated with increased risk of venous thromboembolism (VTE) after spinal surgery. This study aims to determine whether incidental durotomies are associated with increased risk of VTE in patients undergoing lumbar decompression surgery.

METHODS

Adult patients undergoing laminectomy or laminotomy (excluding any with concomitant fusion procedures) for degenerative etiologies and with a minimum of 90-day follow-up were identified from the MSpine Pearldiver dataset. Incidental durotomies were identified based on hospital administrative coding, and patient demographics, comorbidities, and the occurrence and timing of VTE (deep vein thrombosis [DVT] and/or pulmonary embolism) were defined. Univariate and multivariate analyses were performed.

RESULTS

Of 156,488 lumbar decompression patients included in the study, incidental durotomies was noted for 2,036 (1.3%). Markedly more VTEs were observed in the first five days in the incidental durotomies group (P < 0.001) but not incrementally any day after (P > 0.05). On univariate analyses, a significant increased risk of VTE, DVT, and PE was observed (P < 0.001 for each). On multivariate analyses controlling for age, sex, and comorbidities, odds were significantly increased for VTE (Odds ratios = 1.75, P < 0.001) and DVT (OR = 1.70, P < 0.001) but not independently significant for pulmonary embolism.

DISCUSSION

Patients who have incidental durotomies during lumbar laminectomy or laminotomy surgery were found to have increased odds of VTE, primarily in the first five days. Although not all factors associated with this could be directly determined, slower mobilization would seem to be a likely contributing factor. Increasing mobilization and/or adjusting chemoprophylaxis in this group would seem appropriately considered.

Preoperative incidence and risk factors of deep vein thrombosis in patients with an isolated patellar fracture

Purpose

This study aimed to investigate the incidence, location, and related factors of preoperative deep venous thrombosis (DVT) in patients with isolated patellar fractures.

Methods

Patients with an isolated patellar fracture, admitted between January 2013 and December 2019 at our institution, were retrospectively analyzed. Upon admission, patients underwent routine Doppler ultrasound scanning (DUS) of the bilateral lower extremities to detect DVT; those with DVT were assigned to the case group and those without DVT to the control group. Patients in both groups did not perform preoperative off-bed weight-bearing exercises. Data on demographics, comorbidities, and laboratory test results upon admission were extracted. Variables were evaluated between the two groups using univariate analyses, and independent risk factors associated with DVT were identified by logistic regression analysis.

Results

During the study period, 827 patients were included, of whom 5.8% (48/827) were found to have preoperative DVT. In DVT patients, 85.4%(41/48) were injured, 8.3%(4/48) were not injured, and 6.3%(3/48) were lower limbs. Multivariate analysis showed that male (male vs. female, odds ratio, OR = 2.25), delayed from injury to DUS (in each day, OR = 1.29), and elevated plasma D-dimer level (> 0.5 µg/mL, OR = 2.47) were independent risk factors associated with DVT.

Conclusions

Despite the low prevalence of DVT after an isolated patellar fracture, this study underscores the importance of identifying those with a high risk of DVT, especially those with multiple identifiable factors, and encourage the early targeted use of anti-thromboembolic agents to reduce DVT occurrence.

Preoperative prevalence of deep vein thrombosis in patients scheduled to have surgery for degenerative musculoskeletal disorders

Background

Although the incidence of symptomatic pulmonary thromboembolism after elective surgery for degenerative musculoskeletal disorders is comparatively low, it is extremely detrimental to both patients and health-care providers. Therefore, its prevention is mandatory. We aimed to perform a cross-sectional analysis of deep venous thrombosis (DVT) before elective surgery for degenerative musculoskeletal disorders, including total knee arthroplasty (TKA), total hip arthroplasty (THA), and spinal surgery, and identify the factors associated with the incidence of preoperative DVT.

Methods

The clinical data of patients aged ≥ 30 years who underwent TKA or THA, and spine surgery for lumbar or cervical degenerative disorders at our institution were retrospectively collected. D-dimer levels were measured preoperatively in all the patients scheduled for surgery. For the patients with D-dimer levels ≥ 1 µg/mL or who were determined by their physicians to be at high risk of DVT, the lower extremity vein was preoperatively examined for DVT on ultrasonography.

Results

Overall, we retrospectively evaluated 1236 consecutive patients, including 701 men and 535 women. Of the patients, 431 and 805 had D-dimer levels ≥ 1 and < 1 µg/mL, respectively. Of 683 patients who underwent lower extremity ultrasonography, 92 had proximal (n = 7) and distal types (n = 85) of DVT. The preoperative prevalence of DVT was 7.4 %. No patient had the incidence of postoperative symptomatic venous thromboembolism. A multivariate analysis revealed that age ≥ 80 years (odds ratio [OR], 95 % confidence interval [CI]: 2.8, 1.1–7.3), knee surgery (2.1, 1.1–4.0), American Society of Anesthesiologists (ASA) grade 2 (2.8, 1.2–6.8), ASA grades 3 or 4 (3.1, 1.0–9.4), and malignancy (1.9, 1.1–3.2) were significantly associated with DVT incidence.

Conclusions

This is the first study to conduct a cross-sectional analysis of preoperative DVT data of patients scheduled for elective surgery for degenerative musculoskeletal disorders. Although whether screening for preoperative DVT is needed to prevent postoperative symptomatic pulmonary thromboembolism remains to be clarified, our data suggested that DVT should be noted before surgery in the patients with advanced age, knee surgery, high ASA physical status, and malignancy.

Risk factors of deep vein thrombosis of lower extremity in patients undergone gynecological laparoscopic surgery: what should we care

BACKGROUND

Deep vein thrombosis (DVT) significantly influences the prognosis of patients. It's necessary to analyze the risk factors for postoperative DVT in patients undergone gynecological laparoscopic surgery.

METHODS

Patients who underwent gynecological laparoscopic surgery from January 1, 2018 to May 31, 2020 were included. The characteristics and clinical data of DVT and non DVT patients were collected and analyzed. Logistic regression analysis was performed to identify the risk factors of DVT in patients undergone gynecological laparoscopic surgery.

RESULTS

A total of 355 patients undergone gynecological laparoscopic surgery were included, the incidence of postoperative DVT was 11.55%. There were significant differences in the age, hypertension, D-dimer, duration of surgery, intraoperative pneumoperitoneum pressure, duration of days in bed between DVT and non-DVT groups (all p < 0.05), and there were no significant difference in the BMI, diabetes, hyperlipidemia, ASA classification and intraoperative blood transfusion between DVT and non-DVT groups (all p > 0.05). Age > 50 years (OR 4.246, 95% CI 1.234-7.114), hypertension (OR 2.219, 95% CI 1.153-4.591), D-dimer > 0.5 mg/L (OR 3.914, 95% CI 1.083-5.229), duration of surgery ≥ 60 min (OR 2.542, 95% CI 1.101-4.723), intraoperative pneumoperitoneum pressure ≥ 15 mmHg (OR 3.845, 95% CI 1.119-5.218), duration of days in bed > 3 days (OR 1.566, 95% CI 1.182-1.994) was the independent risk factors for DVT in patients undergone gynecological laparoscopic surgery (all p < 0.05).

CONCLUSIONS

The incidence of postoperative DVT in patients undergone gynecological laparoscopic surgery is high, and those high-risk factors should be targeted to intervene in order to reduce the postoperative DVT.

High risk of venous thromboembolism after orthopedic surgery in patients with thrombophilia

OBJECTIVE

This study aimed at evaluating the effect of thrombophilia on the risk of venous thromboembolism (VTE) in patients undergoing any type of orthopedic surgery.

BACKGROUND

Patients undergoing orthopedic surgery are at high risk for VTE. Although patients with thrombophilia have an increased risk of VTE, it is currently unclear whether there is a synergetic effect in patients with thrombophilia who undergo orthopedic surgery.

METHODS

Data from a large population-based case-control study (the Multiple Environmental and Genetic Assessment [MEGA] of risk factors for venous thrombosis study) were used. Odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for age, sex, and body mass index (BMI) (ORadj) were calculated for patients undergoing any orthopedic intervention.

RESULTS

Of 4721 cases and 5638 controls, 263 cases and 94 controls underwent orthopedic surgery. Patients who had any orthopedic intervention in the year before the index date were at higher risk of VTE (ORadj 3.7; 95% CI, 2.9-4.8) than those who did not undergo any orthopedic surgery. There was an additionally increased risk in patients with factor V Leiden (OR 17.5, 95% CI, 4.1-73.6), non-O blood group (OR 11.2; 95% CI, 3.4-34.0), or elevated plasma levels of factor VIII (OR 18.6; 95% CI, 7.4-46.9) all relative to patients without these defects, not undergoing orthopedic surgery.

CONCLUSIONS

Patients with factor V Leiden, high levels of factor VIII, or blood group non-O were found to have a high risk of VTE after orthopedic surgery. Identification of these patients may enable individualized thromboprophylactic treatment to efficiently reduce VTE risk.

Does minimally invasive spine surgery reduce the rate of perioperative medical complications? A retrospective single-center experience of 1435 degenerative lumbar spine surgeries

PURPOSE

It is unclear if minimally invasive techniques reduce the rate of perioperative complications when compared to traditional open approaches to the lumbar spine. Our aim was to evaluate perioperative complications in patients that underwent MIS and conventional open techniques for degenerative lumbar pathology.

METHODS

A retrospective review of a prospectively collected database identified 1435 patients that underwent surgery for degenerative lumbar pathology from January 2013-2016. We evaluated the rates of deep vein thrombosis, pulmonary embolism, urinary tract infection, and pneumonia. Groups were analyzed based on decompression alone as compared with decompression and fusion for both MIS and traditional open techniques.

RESULTS

Patients that underwent traditional open lumbar decompression surgery were more likely to develop a DVT (P = .01) than those undergoing MIS decompression. There was no significant difference in rates of PE (P = .99), UTI (P = .24), or pneumonia (P = .56). Patients that underwent traditional open lumbar fusion surgery compared to MIS fusion were also more likely to have a PE (P = .03). There was no significant difference in rates of DVT (P = .22), UTI (P = .43), or pneumonia (P = .24).

CONCLUSION

Minimally invasive spinal surgery was found to reduce the rate of DVT for decompression surgeries and reduce the rate of PE for fusion surgeries.

Prevalence and Predictors for Preoperative Deep Vein Thrombosis in Patients with Thoracolumbar Fractures Caused by High-Energy Injuries

OBJECTIVE

To determine the prevalence of preoperative deep vein thrombosis (DVT) and to identify the predictors for preoperative DVT in patients with thoracolumbar fractures caused by high-energy injuries.

METHODS

A total of 429 patients with thoracolumbar fractures caused by high-energy injuries from October 2016 to November 2019 were included in this retrospective study. The patients underwent ultrasonography before operation and were divided into the DVT group and non-DVT group. Demographic data and laboratory results were collected, and mechanical and chemical prophylaxis were performed to prevent DVT. The incidence of DVT was evaluated and the predictors of preoperative DVT were identified.

RESULTS

The overall incidence of preoperative DVT was 14.45% (62/429). Of all patients, 1 (0.23%) had proximal DVT and 61 (14.22%) had distal DVT. The incidence of preoperative DVT was 24.59% in patients with thoracic fractures and 11.04% in those with lumbar fractures. Multivariate logistic regression identified 3 predictors, including lower extremity motor (P < 0.001), time from injury to operation (P < 0.001), and D-dimer (P = 0.001). Lower extremity motor score <3, time from injury to operation >3 days, and D-dimer >1.81 mg/L showed satisfied accuracy for predicting preoperative DVT. The receiver operating characteristic curve analysis indicated the diagnostic value of D-dimer was the highest when the area under the receiver operating characteristic curve curve was 0.769.

CONCLUSIONS

Despite mechanical and chemical prophylaxis, the incidence of preoperative DVT is still very high, especially in thoracic fractures. Lower extremity motor score <3, time from injury to operation >3 days, and D-dimer >1.81 mg/L are predictors for preoperative DVT. More attention is warranted to prevent preoperative DVT when ≥2 predictors are present.

Thromboprophylaxis in elective spinal surgery: A protocol for systematic review

BACKGROUND

Venous thromboembolism (VTE) is a serious, sometimes life-threatening complication that can occur following spine surgery. The incidence of VTE, and the optimal type and timing of thromboprophylaxis for this complication in elective spine surgery is a matter of debate.

OBJECTIVE

To perform a systematic review with the aim of clarifying the efficacy and adverse effects of mechanical and chemical prophylaxis for preventing thromboembolic complications in elective spine surgery for conditions other than trauma and malignant disease.

METHODS/DESIGN

A search strategy of related articles up to March 2018 was designed and executed in Medline and Embase.

PATIENTS

adolescents (>10 years) and adults undergoing elective surgery for spinal deformity or degenerative disease (from C1 to S1).

INTERVENTION

Perioperative mechanical and chemical thromboprophylaxis. Studies could be randomized controlled trials or observational studies that reported data on any relevant clinical outcomes.

RESULTS

In total, 2451 uniquecitations were identified and 35 studies were ultimately included in the systematic review. The overall mean incidence of complications was 3.7% for deep venous thrombosis, 0.0% for pulmonary embolism, and 3.7% for bleeding in chemoprophylaxis group; 2.9% for deep venous thrombosis, 0.4% for pulmonary embolism and 0.0% for bleeding in mechanoprophylaxis; and 0.7% for deep venous thrombosis, 0.1% for pulmonary embolism and 0.2% for bleeding in mixed prophylaxis group with no specific data on these rates for the type of patient and type and location of surgery. None of the articles retrieved provided information on the adolescent population.

DISCUSSION AND CONCLUSIONS

The poor design and high variability among the studies regarding characteristics of study population, details of interventions, and definitions of outcomes, determines a low quality of the available evidence and limits the interpretation of the results. We were unable to identify a clear advantage of one type of thromboprophylaxis over the other, although there was an increased risk of bleeding with chemoprophylaxis, which could favor the use of mechanoprophylaxis in this scenario.

Combination of Traditional Chinese Medicine and Low-Molecular-Weight Heparin Prevents Deep Vein Thrombosis After Surgery: A Meta-Analysis

At present, there is no consistent understanding of the effect of traditional Chinese medicine (TCM) prescription in the prevention of the deep vein thrombosis (DVT), though TCM has been widely used in China. To evaluate the efficacy of TCM prescription combined with low-molecular-weight heparin (LMWH) for preventing DVT after major orthopedics surgery. All the retrieved articles were evaluated using specific inclusion and exclusion criteria. Then, data were extracted and evaluated for inclusion in a randomized controlled trial. In this study, variables included relative risk (RR), mean difference (MD), and their corresponding 95% confidence intervals (95% CIs). Overall, 16 articles were included with 1538 patients, 768 in the combination group (combination of TCM prescription and LMWH) and 770 in the LMWH group. The results indicated that in the combination group, the incidence of DVT (RR: 0.34, 95% CI: 0.23-0.50, P < .00001) and d-dimer levels (standardized mean difference: -1.19, 95% CI: -1.80 to -0.58, P = .0001) was significantly lower than that in the LMWH group. Furthermore, the combination treatment obviously decreased the concentration of fibrinogen (MD: -1.19, 95% CI: -2.13 to -0.25, P = .01). The combination of TCM prescription and LMWH could significantly reduce the incidence of DVT, suggesting that it may be a more effective prophylaxis measure for DVT after major orthopedics surgery.

Time-to-event analyses of lower-limb venous thromboembolism in aged patients undergoing lumbar spine surgery: a retrospective study of 1620 patients

After spine surgery, venous thromboembolism (VTE) is not uncommon in aged patients. This study investigates time-to-event risk factors of postoperative VTE based on medical records of aged patients (age≥60 yr) between January 2013 and December 2018. All participants had undergone lower extremity ultrasonography pre- and postoperatively at the first, second, fourth, eighth, and twelfth weeks. Mann-Whitney U tests and chi-square tests were used for univariate analyses, and Cox regression was utilized for multivariate analyses. A total of 1620 cases were recruited, VTE group (N=382, 23.6%) and non-VTE group (N=1238, 76.4%), aged 67 (IQR 11) years and 65 (IQR 6) years, respectively. The univariate analyses indicated significant differences between the VTE and non-VTE groups regarding advanced age, VTE history, hypertension, fusion, hospital stay, FIB, HDL, D-dimer, and TC (all P<0.05). The Cox regression showed that advanced age (OR=1.108; 95% CI, 1.091–1.126), VTE history (OR=4.962; 95% CI, 3.849–6.397), and hypertension (OR=1.344; 95% CI, 1.084–1.667) were the risk factors for postoperative VTE (P<0.05). The time-to-event analyses indicated that the hazard of VTE formation was highest in the first postoperative week. In conclusion, advanced age, VTE history, and hypertension are main risks for VTE formation, particularly in the first postoperative week.