Venous thromboembolism in neurosurgery and neurology patients: a review

Primary endovascular embolisation of intracranial arteriovenous malformations (AVM)-UK single centre experience

PURPOSE

Intracranial arteriovenous malformations (AVMs) treated at our institution with modern techniques of endovascular intervention were analysed for the rate of complete occlusion, associated morbidity, and mortality. To our knowledge, this is the first series from the UK evaluating the effectiveness of endovascular embolisation as a primary treatment for selected cases.

METHODS

All newly referred AVMs between January 2017 and June 2022 were reviewed and those treated with primary endovascular intervention were identified. Details of the endovascular procedures were retrospectively reviewed.

RESULTS

In 5½ years, 41.1% of AVMs referred to our institution have been triaged for primary endovascular intervention. Sixty-eight AVMs were embolised and followed-up: 44 ruptured and 24 unruptured. Spetzler-Martin grading varied from I to III, and a single AVM was grade IV. The approach was arterial in 73.5%, solely venous in 7.4%, and combined in 19.1%. The mean follow-up was 18 months for imaging and 26 months for clinical assessment. Complete obliteration was achieved in 95.6%. Ruptured AVM cohort: The rate of functional deterioration was 13.6%. Unruptured AVM cohort: The rate of functional deterioration secondary to complications from embolisation was 4.2%.

CONCLUSIONS

Endovascular embolisation may be a favourable option for primary AVM treatment in carefully selected patients. However, selection criteria need to be better delineated for more specialists to consider this as a primary therapy.

Thromboembolic prophylaxis in neurosurgical practice: a systematic review

BACKGROUND

In neurosurgical patients, the risk of developing venous thromboembolism (VTE) is high due to the relatively long duration of surgical interventions, usually long immobilization time after surgery, and possible neurological deficits which can negatively influence mobility. In neurosurgical clinical practice, there is lack of consensus on optimal prophylaxis against VTE, mechanical or pharmacological.

OBJECTIVE

To systematically review available literature on the incidence of VTE in neurosurgical interventions and to establish an optimum prevention strategy.

METHODS

A literature search was performed in PubMed, Embase, Web of Science, Cochrane Library, and EmCare, based on a sensitive search string combination. Studies were selected by predefined selection criteria, and risk of bias was assessed by Newcastle-Ottawa Quality Assessment Scale and Cochrane risk of bias.

RESULTS

Twenty-five studies were included, half of which had low risk of bias (21 case series, 3 comparative studies, 1 RCT). VTE was substantially higher if the evaluation was done by duplex ultrasound (DUS), or another systematic screening method, in comparison to clinical evaluation (clin). Without prophylaxis DVT, incidence varied from 4 (clin) to 10% (DUS), studies providing low molecular weight heparin (LMWH) reported an incidence of 2 (clin) to 31% (DUS), providing LMWH and compression stockings (CS) reported an incidence of 6.4% (clin) to 29.8% (DUS), and providing LMWH and intermittent pneumatic compression devices (IPC) reported an incidence of 3 (clin) to 22.3% (DUS). Due to a lack of data, VTE incidence could not meaningfully be compared between patients with intracranial and spine surgery. The reported incidence of pulmonary embolism (PE) was 0 to 7.9%.

CONCLUSION

Low molecular weight heparin, compression stockings, and intermittent pneumatic compression devices were all evaluated to give reduction in VTE, but data were too widely varying to establish an optimum prevention strategy. Systematic screening for DVT reveals much higher incidence percentages in comparison to screening solely on clinical grounds and is recommended in follow-up of neurosurgical procedures with an increased risk for DVT development in order to prevent occurrence of PE.

Venous thromboembolism in aneurysmal subarachnoid hemorrhage: Risk factors and timing of chemoprophylaxis

INTRODUCTION

Venous thromboembolism (VTE) is a significant contributor to morbidity and mortality among patients recovering from aneurysmal subarachnoid hemorrhage (aSAH). Prophylactic heparin reduces the risk of VTE, but the optimal timing for its initiation among aSAH patients remains unclear.

OBJECTIVE

To conduct a retrospective study assessing risk factors for VTE and optimal timing of chemoprophylaxis in patients treated for aSAH.

METHODS

From 2016-2020, 194 adult patients were treated for aSAH at our institution. Patient demographics, clinical diagnoses, complications, pharmacologic interventions, and outcomes were recorded. Risk factors for symptomatic VTE (sVTE) were analyzed via Chi-squared, univariate, and multivariate regression.

RESULTS

In total 33 patients presented with sVTE (25 DVT, 14 PE). Patients with sVTE had longer hospital stays (p < 0.01) and worse outcomes at one-month (p < 0.01) and three-month follow-up (p = 0.02). Univariate predictors of sVTE included male sex (p = 0.03), Hunt Hess score (p = 0.01), Glasgow Coma scale (p = 0.02), intracranial hemorrhage (p = 0.03), hydrocephalus requiring external ventricular drain (EVD) placement (p < 0.01), and mechanical ventilation (p < 0.01). Only hydrocephalus requiring EVD (p = 0.01) and ventilator use (p = 0.02) remained significant upon multivariate analysis. Patients with delayed heparin introduction were significantly more likely to sustain sVTE on univariate analysis (p = 0.02) with a trend-level significance on multivariate analysis (p = 0.07).

CONCLUSIONS

Patients with aSAH are more likely to develop sVTE following use of perioperative EVD or mechanical ventilation. sVTE leads to longer hospital stays and worse outcomes among patients treated for aSAH. Delayed heparin initiation increases the risk of sVTE. Our results may help guide surgical decision-making during recovery from aSAH and improve VTE-related postoperative outcomes.

Low awareness of venous thromboembolism among neurosurgical hospitalized patients: a cross-sectional study

BACKGROUND

Venous thromboembolism (VTE) including Deep Venous Thrombosis (DVT) and Pulmonary Embolism (PE), is a serious cause of patient morbidity and mortality in hospitals. Neurosurgical hospitalized patients have higher rates of immobility and bed rest, thus increasing their risk of developing VTE. This highlights the need for their thromboprophylaxis regimens. Patients' awareness of VTE is essential for promoting strategies such as early ambulation and encouraging self-assessment and self-reporting of VTE signs and symptoms. This study evaluated neurosurgical hospitalized patients' awareness of VTE and explored the influencing factors to provide a theoretical basis for nursing intervention.

METHODS

We selected one tertiary level hospital in Hunan Province and randomly sampled eligible patients from each five neurosurgical units. We conducted a cross-sectional survey of the hospitalized patients of neurosurgery using the self-designed and validated VTE knowledge questionnaire, and the influencing factors were analyzed using SPSS 26.0.

RESULTS

A total of 386 neurosurgical hospitalized patients completed the survey. The score of VTE knowledge in neurosurgical hospitalized patients was 13.22 (SD = 11.52). 36.0% and 21.2% of participants reported they had heard of DVT and PE, respectively. 38.9% of participants were unable to correctly identify any symptoms of VTE. The most frequently identified risk factor was 'immobility or bed rest for more than three days' (50.0% of participants), and 38.1% of patients agreed that PE could cause death. 29.5% of participants were unable to identify any prophylactic measures of VTE. The results of Negative Binomial Regression showed that the influencing factors of VTE knowledge in neurosurgical hospitalized patients were education level (P < 0.004) and sources of information related to VTE, including nurses (95% CI = 2.201-4.374, P < 0.001), and family member/friend (95% CI = 2.038-4.331, P < 0.001), Internet/TV (95% CI = 1.382-2.834, P < 0.001). Other sources included patient /pamphlet/poster /professional books (95% CI = 1.492-3.350, P < 0.001).

CONCLUSIONS

This study demonstrates the lack of awareness of VTE among neurosurgical hospitalized patients. More attention must be paid to carrying out training on VTE knowledge according to different characteristics of neurosurgical hospitalized patients, so as to ensure safe and high-quality patient care.

Safety and Effectiveness of First-line Endovascular Management of Low-Grade Brain Arteriovenous Malformations : Single Center Experience in 145 Patients

PURPOSE

Spetzler-Martin grade (SMG) I-II (low-grade) brain arteriovenous malformations (BAVMs) are often considered safe for microsurgical resection; however, the role of endovascular treatment (EVT) remains to be clarified in this indication, especially for unruptured BAVMs. The purpose of our study was to assess the safety and effectiveness of endovascular treatment as the first-line treatment for low-grade BAVMs.

METHODS

From our local database, we retrospectively retrieved patients with low-grade BAVMs, either ruptured or unruptured, treated by embolization as first-line treatment in our department between January 2005 and January 2020. The primary endpoint was the total obliteration rate of BAVMs, and secondary endpoints were hemorrhagic complications and final clinical outcome, assessed through shift of the modified Rankin scale, and mortality rate secondary to BAVM embolization.

RESULTS

A total of 145 patients meeting inclusion criteria and treated by EVT as first-line therapy were included in the study (82 ruptured and 63 unruptured BAVMs). Overall, complete exclusion of BAVMs was achieved in 110 patients (75.9%); 58 patients (70.7%) with ruptured and 52 (82.5%) unruptured BAVMs, including 37.9% BAVMs excluded by EVT alone (35.5% among ruptured and 44.4% among unruptured BAVMs) and 38% by combined treatment (EVT and surgery or EVT and SRS). There was no BAVM volume cut-off predictive for total obliteration by embolization alone. Early minor hemorrhagic complications were reported in 14 patients (9.6%) and early major hemorrhagic complications were reported in 5 patients (3.4%). No late hemorrhagic complications (0%) occurred; mortality rate was 0.7% (1/145 patients). Improved/unchanged mRS was reported in 137 patients (94.5%).

CONCLUSION

Endovascular treatment alone or associated with others exclusion techniques, might be safe and effective for complete exclusion of low-grade brain arteriovenous malformations regardless of the volume.

Wide Dissection Trans-Sulcal Approach for Resection of Deep Intra-Axial Lesions in Eloquent Brain Areas

Introduction: Resection of intra-axial tumors (IaT) in eloquent brain regions risks major postoperative neurological deficits. Awake craniotomy is often used to navigate these areas; however, some patients are ineligible for awake procedures. The trans-sulcal approach (TScal) was introduced to reduce parenchymal trauma during tumor resection. We report our experiences utilizing TScal for resection of deep IaT located in eloquent areas. Materials and Methods: This is a single-center retrospective analysis of patients who underwent IaT resection in eloquent areas via TScal from January 2013 to April 2021. Seventeen cases were reviewed, and relevant data was collected. Fluorescence-guided surgery with 5-aminolevulinic acid (ALA) and intraoperative ultrasound was performed in some cases. Results: Seventeen patients (10 males, 7 females) averaging 61.2 years-old (range, 21-76) were included in this study. Average length of stay was 4.8 days, and only 2 patients (11.8%) required hospital readmission within 30 days. Gross total resection (GTR) was achieved in 15 patients (88.2%), while subtotal resection occurred in 2 patients (11.8%). Eleven patients (64.7%) reported full resolution of symptoms, 4 patients (23.5%) reported deficit improvement, and 2 patients (11.8%) experienced no change from their preoperative deficits. No patient developed new permanent deficits postoperatively. Discussion: GTR, preoperative deficit reduction, and complications were comparable to awake craniotomy and other TScal studies. Ancillary intraoperative techniques, such as brain mapping, 5-ALA and intraoperative ultrasound, are afforded by TScal to improve resection rates and overall outcomes. Conclusions: TScal can be an option for patients with deep lesions in eloquent areas who are not candidates for awake surgeries.

Between scylla and charybdis: risks of early therapeutic anticoagulation for venous thromboembolism after acute intracranial hemorrhage

OBJECTIVE

To assess the risk of hematoma expansion in patients with acute intracranial hemorrhage (ICH) requiring therapeutic anticoagulation for the treatment of venous thromboembolism.

METHODS

We retrospectively reviewed all patients at our institution between 2014 and 2019 who were therapeutically anticoagulated for venous thromboembolism within 4 weeks after ICH. We included subtypes of traumatic ICH and spontaneous intraparenchymal hemorrhage. Our main outcome was the incidence of hematoma expansion within 14 days from initiating therapeutic anticoagulation. Hematoma expansion was defined as (1) radiographically proven expansion leading to cessation of therapeutic anticoagulation or (2) death due to hematoma expansion. Secondary outcomes included mortality due to hematoma expansion and characteristics associated with hematoma expansion.

RESULTS

Fifty patients met inclusion criteria (mean age: 54 years, 80% male, 76% Caucasian); 24% had undergone a neurosurgical procedure prior to therapeutic anticoagulation. Median time from ICH to therapeutic anticoagulation initiation was 9.5 days (IQR 4-17), 40% received therapeutic anticoagulation in <7 days after ICH. Six patients (12%) developed hematoma expansion, of whom two (4%) died. While not statistically significant, patients with hematoma expansion tended to be older (57.8 vs. 53.5 years), were anticoagulated sooner (4 vs. 10 days), presented with lower GCS (50% vs. 39% with GCS <8), higher hematoma volume (50% vs. 42% >30 cc), and higher SDH diameter (16 mm vs. 8.35 mm). There was a trend towards greater risk of hematoma expansion for patients undergoing endoscopic ICH evacuation (16% vs. 2%, p = 0.09); patients with hematoma expansion were more likely to present with hydrocephalus (67% vs. 16%, p = 0.02).

CONCLUSIONS

Our study is among the first to explore characteristics associated with hematoma expansion in patients undergoing therapeutic anticoagulation after acute ICH. Larger studies in different ICH subtypes are needed to identify determinants of hematoma expansion in this high-acuity population.

Supraprophylactic Anti-Factor Xa Levels Are Associated with Major Bleeding in Neurosurgery Patients Receiving Prophylactic Enoxaparin

BACKGROUND

Prior studies demonstrated reduced risk for venous thromboembolism (VTE) in neurosurgical patients secondary to prophylaxis with both heparin and low-molecular-weight heparin. The ability to monitor low-molecular-weight heparin by obtaining anti-factor Xa (anti-Xa) serum levels provides an opportunity to evaluate safety and efficacy. The aim of this study was to describe characteristics of patients who have anti-Xa levels outside of the goal range (0.2-0.4/0.5 IU/mL) and investigate incidence of major bleeding and VTE.

METHODS

A single-center, retrospective, observational study was conducted on neurosurgical patients receiving enoxaparin for VTE prophylaxis between August 2019 and December 2020. Significance testing was conducted via Fisher exact test and independent samples t test.

RESULTS

The study included 85 patients. Patients were less likely to have an anti-Xa level in the goal range if they were male, had a higher weight, or were morbidly obese. Three neuroendovascular patients (3.5%) experienced a major bleed. Serum anti-Xa levels were significantly higher in patients who experienced major bleeds compared with patients who did not (0.45 ± 0.16 IU/mL vs. 0.28 ± 0.09 IU/mL, P = 0.003). Patients with a supraprophylactic anti-Xa level (>0.5 IU/mL) were more likely to experience a major bleed (P = 0.005). One VTE event occurred: the patient experienced a pulmonary embolism with anti-Xa level at goal.

CONCLUSIONS

Anti-Xa-guided enoxaparin dosing for VTE prophylaxis in neurosurgical patients may help prevent major bleeding. These data suggest that a higher anti-Xa level may predispose patients to major bleeding. Further evaluation is needed to identify the goal anti-Xa level for VTE prophylaxis in this population.

Unfractionated Heparin TID Dosing Regimen Is Associated With a Lower Rate of Pulmonary Embolism When Compared With BID Dosing in Patients Undergoing Craniotomy

BACKGROUND

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), and intracranial hemorrhage (ICH) may complicate the post-operative course of patients undergoing craniotomy. While prophylaxis with unfractionated heparin (UFH) has been shown to reduce VTE rates, twice-daily (BID) and three-times-daily (TID) UFH dosing regimens have not been compared in neurosurgical procedures. The objective of this study was to explore the association between UFH dosing regimen and rates of VTE and ICH in craniotomy patients.

METHODS

A retrospective chart review was conducted for 159 patients at Northwestern University receiving 5000 units/0.5 mL UFH injections either BID (n = 132) or TID (n = 27). General linear regression models were run to predict rates of DVT, PE, and reoperation due to bleeding from UFH dosing regimen while controlling for age at surgery, sex, VTE history, craniotomy for tumor resection, surgery duration, length of stay, reoperation, infections, and IDH/MGMT mutations.

RESULTS

Receiving UFH TID was significantly associated with a lower rate of PE when compared with receiving UFH BID (β = -0.121, P = 0.044; TID rate = 0%, BID rate = 10.6%). UFH TID also showed a trend toward lower rates of DVT (β = -0.0893, P = 0.295; TID rate = 18.5%, BID rate = 21.2%) when compared with UFH BID. UFH TID showed no significant difference in rate of reoperation for bleeding when compared to UFH BID (β = -0.00623, P = 0.725; TID rate = 0%, BID rate = 0.8%).

CONCLUSIONS

UFH TID dosing is associated with lower rates of PE when compared with BID dosing in patients undergoing craniotomy.

Posterior Fossa Hemorrhage Following the Use of Low-Molecular-Weight Heparin: Lessons Learned and Recommendations for the Treatment and Prophylaxis of Postoperative Venous Thromboembolism

Introduction Venous thromboembolism (VTE) is the most common preventable cause of morbidity and mortality among neurosurgery patients. Several studies have concluded that the use of chemical prophylaxis among patients undergoing a craniotomy reduces the incidence of VTE, and it is presumed to be safe. However, these studies do not differentiate between a supratentorial and posterior fossa craniotomy. Furthermore, the prophylactic or therapeutic use of low-molecular-weight heparin (LMWH) has been reported to increase the risk of intracranial hemorrhage. In this study, we describe the clinical details and outcomes for all patients who underwent posterior fossa craniotomy and developed posterior fossa hemorrhage secondary to postoperative use of LMWH during the study period. We also propose recommendations pertaining to postoperative heparin use after posterior fossa surgeries. Methods Data were retrospectively collected for patients presenting with posterior fossa hemorrhage following anticoagulant use among those who previously underwent posterior fossa craniotomy by the senior author (R.W.P.) from January 1, 2011, through December 31, 2018. Results We identified five patients who experienced postoperative hemorrhage while receiving LMWH in the initial setting of posterior fossa craniotomy. After hemorrhaging, four patients had low Glasgow Outcome Scale (GOS) scores (≤3) and failed to return to their baseline neurological status. These four patients had a Glasgow Coma Scale (GCS) score of 15/15 in the immediate postoperative period and received heparin within 72 hours of surgery. Conclusions Based on our findings, there is a possible association between the increased risk of hemorrhage and the early postoperative use of LMWH. The debilitating outcomes among the majority of these patients warrant the cautious use and further investigation of postoperative LMWH to appropriately quantify the risk. Further comparative studies with a larger sample size are required to provide insight into the pathophysiology of our findings.

Pharmacologic thromboprophylaxis in adult patients undergoing neurosurgical interventions for preventing venous thromboembolism

The impact of pharmacologic prophylaxis for venous thromboembolism in patients undergoing neurosurgical intervention remains uncertain. We reviewed the efficacy and safety of pharmacologic compared with nonpharmacologic thromboprophylaxis in neurosurgical patients. Three databases were searched through April 2018, including those for randomized controlled trials (RCTs) and for nonrandomized controlled studies (NRSs). Independent reviewers assessed the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Seven RCTs and 3 NRSs proved eligible. No studies reported on symptomatic proximal and distal deep vein thrombosis (DVT). Two RCTs reported on screening-detected proximal and distal DVTs. We used the findings of these 2 RCTs as the closest surrogate outcomes to inform the proximal and distal DVT outcomes. These 2 RCTs suggest that pharmacologic thromboprophylaxis may decrease the risk of developing asymptomatic proximal DVT (relative risk [RR], 0.50; 95% confidence interval [CI], 0.30-0.84; low certainty). Findings were uncertain for mortality (RR, 1.27; 95% CI, 0.57-2.86; low certainty), symptomatic pulmonary embolism (PE) (RR, 0.84; 95% CI, 0.03-27.42; very low certainty), asymptomatic distal DVT (RR, 0.54; 95% CI, 0.27-1.08; very low certainty), and reoperation (RR, 0.43; 95% CI, 0.06-2.84; very low certainty) outcomes. NRSs also reported uncertain findings for whether pharmacologic prophylaxis affects mortality (RR, 0.72; 95% CI, 0.46-1.13; low certainty) and PE (RR, 0.18; 95% CI, 0.01-3.76). For risk of bleeding, findings were uncertain in both RCTs (RR, 1.57; 95% CI, 0.70-3.50; low certainty) and NRSs (RR, 1.45; 95% CI, 0.30-7.12; very low certainty). In patients undergoing neurosurgical procedures, low certainty of evidence suggests that pharmacologic thromboprophylaxis confers benefit for preventing asymptomatic (screening-detected) proximal DVT with very low certainty regarding its impact on patient-important outcomes.

Impaired contraction of blood clots precedes and predicts postoperative venous thromboembolism

Deep vein thrombosis (DVT) is a common but unpredictable complication of surgical interventions. To reveal an association between the blood clot contraction (retraction) and the incidence of postoperative venous thrombosis, 78 patients with brain tumors that were operated on were studied, of which 23 (29%) were diagnosed with postoperative DVT. A clot contraction assay, along with other hemostatic and hematologic tests, was performed 1–3 days before the surgery and on the 1st day and 5–7th days after the surgery. On the 1st postoperative day, clot contraction was significantly suppressed in patients who subsequently developed DVT, compared to the patients without DVT. Importantly, this difference was observed at least 5 days before DVT had developed. The weakening of contraction on the 1st postoperative day was more pronounced in the DVT patients with malignant versus benign brain tumors, atherosclerosis, hypertension, as well as in patients receiving steroids before and during the operation. These results indicate that impaired clot contraction in the postoperative period is associated with imminent DVT, suggesting that it is a prothrombotic risk factor and promotional mechanism. The clot contraction assay has a predictive value in assessing the threat of postoperative thrombosis in patients with benign and malignant brain tumors.

Perioperative anticoagulation in patients with intracranial meningioma: No increased risk of intracranial hemorrhage?

OBJECTIVE

Anticoagulation (AC) is a critical topic in perioperative and post-bleeding management. Nevertheless, there is a lack of data about the safe, judicious use of prophylactic and therapeutic anticoagulation with regard to risk factors and the cause and modality of brain tissue damage as well as unfavorable outcomes such as postoperative hemorrhage (PH) and thromboembolic events (TE) in neurosurgical patients. We therefore present retrospective data on perioperative anticoagulation in meningioma surgery.

METHODS

Data of 286 patients undergoing meningioma surgery between 2006 and 2018 were analyzed. We followed up on anticoagulation management, doses and time points of first application, laboratory values, and adverse events such as PH and TE. Pre-existing medication and hemostatic conditions were evaluated. The time course of patients was measured as overall survival, readmission within 30 days after surgery, as well as Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS). Statistical analysis was performed using multivariate regression.

RESULTS

We carried out AC with Fraxiparin and, starting in 2015, Tinzaparin in weight-adapted recommended prophylactic doses. Delayed (216 ± 228h) AC was associated with a significantly increased rate of TE (p = 0.026). Early (29 ± 21.9h) prophylactic AC, on the other hand, did not increase the risk of PH. We identified additional risk factors for PH, such as blood pressure maxima, steroid treatment, and increased white blood cell count. Patients' outcome was affected more adversely by TE than PH (+3 points in modified Rankin Scale in TE vs. +1 point in PH, p = 0.001).

CONCLUSION

Early prophylactic AC is not associated with an increased rate of PH. The risks of TE seem to outweigh those of PH. Early postoperative prophylactic AC in patients undergoing intracranial meningioma resection should be considered.

Clinical Predictive Factors of Lower Extremity Deep Vein Thrombosis in Relative High-Risk Patients after Neurosurgery: A Retrospective Study

INTRODUCTION

It is acknowledged that patients undergoing neurosurgery with neurological illness are at higher risk of lower extremity deep vein thrombosis (DVT). As an underlying life-threatening complication, the incidence and risk factors for high-risk patients with lower extremity deep vein thrombosis are still controversial in relative high-risk patients after neurosurgery.

MATERIALS AND METHODS

A total of 204 patients who underwent neurosurgery and were considered as a high-risk group of DVT according to times of stay in bed more than 3 days were enrolled in this study. We evaluated the lower extremity DVT by using Color Doppler Ultrasound System (CDUS). Clinical parameters of patients at the time of admission and postoperation were recorded and prepared for further analysis. Early predictive factors for postoperative lower extremity DVT were established. Diagnostic performance of predictive factors was evaluated by using receiver operating characteristic (ROC) curve analysis.

RESULTS

The overall incidence rate of DVT in 204 enrolled patients was 30.9%. Multivariate logistic regression indicated that hypertension (OR 3.159, 95% CI 1.465-6.816; P = 0.003), higher postoperative D-dimer (OR 1.225, 95% CI 1.016-1.477; P = 0.034), female (OR 0.174, 95% CI 0.054-0.568; P = 0.004), and lower GCS score (OR 0.809, 95% CI 0.679-0.965; P = 0.013) were independently associated with incidence of DVT in patients after neurosurgery. The logistic regression function (LR model) of these four independent risk factors had a better performance on diagnostic value of DVT in patients after neurosurgery.

CONCLUSION

The combined factor was constructed by hypertension, postoperative D-dimer, gender, and GCS score, and it might be a more handy and reliable marker to stratify patients at risk of DVT after neurosurgery.

Incidence of venous thromboembolism in hospitalized pediatric neurosurgical patients: a retrospective 25-year institutional experience

PURPOSE

Venous thromboembolism (VTE) refers to both deep venous thrombosis (DVT) and pulmonary embolism (PE). The risk of VTE in adult neurosurgical patients is thoroughly studied. However, the incidence and risk of VTE in a comprehensive pediatric neurosurgical population is not well-defined. The available pediatric data consists of reviews of specific high-risk groups, such as trauma, critical care, or cancer patients. This may not be reflective of the entire spectrum of a high-volume pediatric neurosurgery practice. This study was undertaken to analyze the incidence and risk factors of VTE in all hospitalizations evaluated by a pediatric neurosurgery service over a 25-year period.

METHODS

A retrospective review of electronic medical records was performed for 9149 hospitalizations in 6374 unique patients evaluated by the pediatric neurosurgery service at Riley Hospital for Children (Indianapolis, IN, USA) from 1990-2014. During this time period, there was no standardized VTE prevention protocol. The study group included all patients less than 18 years of age. Patients with a known pre-existing VTE or pregnancy were excluded.

RESULTS

VTE was diagnosed in 20 of the 9149 (0.22%) hospitalizations, in 18 unique patients. All DVTs were diagnosed via Doppler ultrasound and/or computed tomography. Anatomic clot locations included 9 in the upper extremity (0.098% of hospitalizations), 8 in the lower extremity (0.087%), and 4 (0.044%) pulmonary emboli. Ten of the 20 occurred in hospitalizations where the patient underwent surgery, although the need for surgery was not a statistically significant risk factor. Sixteen of the 20 (80%) occurred in patients with at least one form of central venous line (p < 0.00001). There was one VTE-related death (0.01%).

CONCLUSIONS

In all pediatric neurosurgical patients, a VTE was found in 0.22% of hospitalizations over a 25-year span. Statistically significant risk factors for VTE included central venous line placement, paralysis, malignancy, intubation greater than 48 h, and hypercoagulable state.

What Is the Safety and Efficacy of Chemical Venous Thromboembolism Prophylaxis Following Vestibular Schwannoma Surgery?

OBJECTIVE

The benefit of routine chemical prophylaxis use for venous thromboembolism (VTE) prevention in skull base surgery is controversial. Chemical prophylaxis can prevent undue morbidity and mortality, however there are risks for hemorrhagic complications.

STUDY DESIGN

Retrospective case-control.

METHODS

A retrospective chart review of patients who underwent surgery for vestibular schwannoma from 2011 to 2016 was performed. Patients were divided by receipt of chemical VTE prophylaxis. Number of VTEs and hemorrhagic complications (intracranial hemorrhage, abdominal hematoma, and postauricular hematoma) were recorded.

RESULTS

One hundred twenty-six patients were identified, 55 received chemical prophylaxis, and 71 did not. All the patients received mechanical prophylaxis. Two patients developed a deep vein thrombosis (DVT) and one patient developed a pulmonary embolism (PE). All patients who developed a DVT or PE received chemical prophylaxis. There was no difference in DVT (p = 0.1886) or PE (p = 0.4365) between those who received chemical prophylaxis and those who did not. Five patients developed a hemorrhagic complication, two intracranial hemorrhage, three abdominal hematoma, and zero postauricular hematoma. All five patients with a complication received chemical prophylaxis (p = 0.00142). The relative risk of a hemorrhagic complication was 14.14 (95% CI = 0.7987-250.4307; p = 0.0778).

CONCLUSION

There was a significant difference between the number of hemorrhagic complications but not between numbers of DVT or PE. Mechanical and chemical prophylaxis may lower the risk of VTE but in our series, hemorrhagic complications were observed. These measures should be used selectively in conjunction with early ambulation.

Retrievable inferior vena cava filters in neurosurgical patients: Retrieval rates and clinical outcomes

OBJECTIVE

To assess inferior vena cava (IVC) filter retrieval rates and clinical outcomes in neurosurgical patients and to determine patient characteristics associated with filter retrieval.

PATIENTS AND METHODS

This single-center retrospective study included 204 consecutive neurosurgical patients (120 men, 84 women; mean age 60 ± 13 years) who underwent retrievable IVC filter insertion between 1/2011-9/2013. Institutional IVC filter database review was used to identify demographic and clinical data, indication for IVC filtration, and IVC filter type. Patients were followed clinically by the neurosurgical, hematology, and interventional radiology services until removal or conversion to a permanent device. Measured outcomes included filter retrieval rates and parameters associated with device removal.

RESULTS

The majority of filters were placed for venous thromboembolism (200/204, 98%). Of 204 filters, 38(19%) were retrieved at median 186 days post-placement (range 3-665 days), 112(55%) converted to permanent devices, 44(22%) patients were deceased, and 10(5%) patients were lost to follow-up after transfer to an outside healthcare facility. Patients with subarachnoid hemorrhage (18% vs. 35%, p = 0.025) and malignancy (5% vs. 25%, p = 0.009) were less likely to have filters removed. Filter type (p = 0.475), gender (p = 0.221), neurosurgical procedure (p = 0.639), and insurance status (p = 0.207) did not demonstrate a significant association with filter retrieval.

CONCLUSION

IVC filter retrieval rates in neurosurgical patients are low despite tracking patients clinically in a multidisciplinary setting. Those neurosurgical patients with intracranial hemorrhage or malignancy requiring IVC filters have a lower likelihood of filter retrieval and may benefit from use of permanent devices.

Reduced risk of venous thromboembolism with the use of intermittent pneumatic compression after craniotomy: a randomized controlled prospective study

OBJECTIVE

The term "venous thromboembolism" (VTE) subsumes deep venous thrombosis (DVT) and pulmonary embolism. The incidence of DVT after craniotomy was reported to be as high as 50%. Even clinically silent DVT may lead to potentially fatal pulmonary embolism. The risk of VTE is correlated with duration of surgery, and it appears likely that it develops during surgery. The present study aimed to evaluate intraoperative use of intermittent pneumatic compression (IPC) of the lower extremity for prevention of VTE in patients undergoing craniotomy.

METHODS

A total of 108 patients undergoing elective craniotomy for intracranial pathology were included in a single-center controlled randomized prospective study. In the control group, conventional compression stockings were worn during surgery. In the treatment group, IPC of the calves was used in addition. The presence of DVT was evaluated by Doppler sonography pre- and postoperatively.

RESULTS

Intraoperative use of IPC led to a significant reduction of VTE (p = 0.029). In logistic regression analysis, the risk of VTE was approximately quartered by the use of IPC. Duration of surgery was confirmed to be correlated with VTE incidence (p < 0.01); every hour of surgery increased the risk by a factor of 1.56.

CONCLUSIONS

Intraoperative use of IPC significantly lowers the incidence of potentially fatal VTE in patients undergoing craniotomy. The method is easy to use and carries no additional risks.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: randomized controlled trial; evidence: class I.Clinical trial registration no.: DRKS00011783 (https://www.drks.de).

The role of preoperative deep vein thrombosis screening in neurooncology

OBJECTIVEVenous thromboembolism (VTE) is a major cause of morbidity in patients undergoing neurosurgical intervention. The authors postulate that the introduction of a routine preoperative deep vein thrombosis (DVT) screening protocol for patients undergoing neurosurgical intervention for brain tumors would result in a more effective diagnosis of DVT in this high-risk subgroup, and subsequent appropriate management of the condition would reduce pulmonary embolism (PE) rates and improve patient outcomes.METHODSThe authors conducted a prospective study of 115 adult patients who were undergoing surgical intervention for a brain tumor. All patients underwent preoperative lower-limb Doppler ultrasonography scanning for DVT screening. Patients with confirmed DVT underwent a period of anticoagulation therapy, which was stopped prior to surgery. An inferior vena cava (IVC) filter was inserted to cover the perioperative period during which anticoagulation therapy was avoided due to bleeding risk before restarting the therapy at a later date. Patients underwent follow-up performed by a neurooncology multidisciplinary team, and subsequent complications and outcomes were recorded.RESULTSSeven (6%) of the 115 screened patients had DVT. Of these patients, one developed postoperative PE, and another had bilateral DVT postoperatively. None of the patients without preoperative DVT developed VTE postoperatively. Age, symptoms of DVT, and previous history of VTE were significantly higher in the group with preoperative DVT. There were no deaths and no complications from the anticoagulation or IVC filter insertion.CONCLUSIONSPreoperative screening for DVT is a worthwhile endeavor in patients undergoing neurosurgical intervention. A multidisciplinary approach in management of anticoagulation and IVC filter insertion is safe and can minimize further VTE in such patients.

Predictors of Venous Thromboembolism After Nonemergent Craniotomy: A Nationwide Readmission Database Analysis

BACKGROUND

Venous thromboembolism (VTE) is responsible for many hospital readmissions each year, particularly among postsurgical cohorts. Because early and indiscriminate VTE prophylaxis carries catastrophic consequences in postcraniotomy cohorts, identifying factors associated with a high risk for thromboembolic complications is important for guiding postoperative management.

OBJECTIVE

To determine VTE incidence in patients undergoing nonemergent craniotomy and to evaluate for factors that predict 30-day and 90-day readmission with VTE.

METHODS

The 2010-2014 cohorts of the Nationwide Readmissions Database were used to generate a large heterogeneous craniotomy sample.

RESULTS

There were 89,450 nonemergent craniotomies that met inclusion criteria. Within 30 days, 1513 patients (1.69%) were readmitted with VTE diagnoses; among them, 678 (44.8%) had a diagnosis of deep vein thrombosis alone, 450 (29.7%) had pulmonary embolism alone, and 385 (25.4%) had both. The corresponding 30-day deep vein thrombosis and pulmonary embolism incidences were 1.19% and 0.93%, respectively. In multivariate analysis, several factors were significantly associated with VTE readmission, namely, craniotomy for tumor, corticosteroids, advanced age, greater length of stay, and discharge to institutional care.

CONCLUSIONS

Craniotomies for tumor, corticosteroids, advanced age, prolonged length of stay, and discharge to institutional care are significant predictors of VTE readmission. The implication of steroids, coupled with their ubiquity in neurosurgery, makes them a potentially modifiable risk factor and a prime target for VTE reduction in craniotomy cohorts. Furthermore, the fact that dose is proportional to VTE risk in the literature suggests that careful consideration should be given toward decreasing regimens in situations in which use of a lower dose might prove equally sufficient.

Chemical venous thromboembolism prophylaxis in neurosurgical patients: an updated systematic review and meta-analysis

OBJECTIVE

Venous thromboembolism (VTE) is a common and potentially life-threatening complication. The risk of serious hemorrhagic complications when starting chemical prophylaxis for VTE prevention is a substantial concern for neurosurgeons. The objective of this study was to perform an updated systematic review and meta-analysis to determine if the rates of VTE and bleeding complications are different in patients undergoing chemoprophylaxis compared with placebo or mechanical prophylaxis alone following cranial or spinal procedures.

METHODS

In February 2016 a systematic literature review was performed identifying 3944 articles from 4 different databases. A random-effects meta-analysis was performed after identifying the articles that met inclusion criteria.

RESULTS

Nine articles that met the inclusion criteria were included. The quality of the studies was good, with all of them being classified as Level 2 evidence, with moderate Jadad scores. A meta-analysis comparing chemoprophylaxis with placebo in the prevention of deep venous thrombosis showed a significant benefit to chemical prophylaxis (OR 0.51, 95% CI 0.37–0.71; p < 0.0001). No significant increase in major intracranial hemorrhage (p = 0.60), major extracranial hemorrhage (p = 0.98), or minor bleeding complications (p = 0.60) was found.

CONCLUSIONS

Based on moderate-to-good quality of evidence, chemoprophylaxis is beneficial in preventing VTE, with no significant increase in either major or minor bleeding complications in patients undergoing cranial and spinal procedures. Further research is needed to determine whether this conclusion holds true for more specific subpopulations.

Venous Thromboembolism during Interventional MRI-Guided Stereotactic Surgery

BACKGROUND/AIMS

Interventional MRI (iMRI) allows real-time confirmation of electrode and microcatheter location in anesthetized patients; however, MRI-compatible pneumatic compression devices (PCD) to reduce the periprocedural venous thromboembolism (VTE) risk are not commercially available. Given the paucity of literature on VTE following iMRI surgery, better characterizing patients suffering this complication and the incidence of this event following iMRI procedures is pivotal for defining best surgical practices. We aim to investigate the incidence of postoperative VTE in iMRI procedures without the use of PCD.

METHODS

Medical records and operative times of patients were retrospectively reviewed. Patient demographics and mean surgical durations were reported with statistical comparisons via ANOVA and the 2-tailed Student t test, an α of 0.05, and the Bonferroni correction. Patients experiencing postoperative VTE underwent an in-depth chart review.

RESULTS

Two out of two hundred ten (0.95%) iMRI procedures resulted in postoperative VTE events. There were statistically significant differences in procedure times between unilateral electrode (157.5 ± 5.7 min), bilateral electrode (193.6 ± 2.9 min), and bilateral gene therapy procedures (467.3 ± 26.5 min). Both patients had longer-than-average operative times for their respective procedures.

CONCLUSIONS

The incidence of postoperative VTE is low following iMRI procedures, even without the use of PCD during surgery.

Percentage change in hemoglobin level and morbidity in spine surgery patients

OBJECTIVE

The aim of this study was to characterize the association between percentage change in hemoglobin (ΔHb)—i.e., the difference between preoperative Hb and in-hospital nadir Hb concentration—and perioperative adverse events among spine surgery patients.

METHODS

Patients who underwent spine surgery at the authors’ institution between December 4, 2008, and June 26, 2015, were eligible for this retrospective study. Patients who underwent the following procedures were included: atlantoaxial fusion, subaxial anterior cervical fusion, subaxial posterior cervical fusion, anterior lumbar fusion, posterior lumbar fusion, lateral lumbar fusion, excision of intervertebral disc, and excision of spinal cord lesion. Data on intraoperative transfusion were obtained from an automated, prospectively collected, anesthesia data management system. Data on postoperative hospital transfusions were obtained through an Internet-based intelligence portal. Percentage ΔHb was defined as: ([preoperative Hb − nadir Hb]/preoperative Hb) × 100. Clinical outcomes included in-hospital morbidity and length of stay associated with percentage ΔHb.

RESULTS

A total of 3949 patients who underwent spine surgery were identified. Of these, 1204 patients (30.5%) received at least 1 unit of packed red blood cells. The median nadir Hb level was 10.6 g/dl (interquartile range 8.7–12.4 g/dl), yielding a mean percentage ΔHb of 23.6% (SD 15.4%). Perioperative complications occurred in 234 patients (5.9%) and were more common in patients with a larger percentage ΔHb (p = 0.017). Hospital-related infection, which occurred in 60 patients (1.5%), was also more common in patients with greater percentage ΔHb (p = 0.001).

CONCLUSIONS

Percentage ΔHb is independently associated with a higher risk of developing any perioperative complication and hospital-related infection. The authors’ results suggest that percentage ΔHb may be a useful measure for identifying patients at risk for adverse perioperative events.

Risk of Deep vein thrombosis in neurosurgery: State of the art on prophylaxis protocols and best clinical practices

OBJECTIVE

To analytically discuss some protocols in Deep vein thrombosis (DVT)/pulmonary Embolism (PE) prophylaxis currently use in Neurosurgical Departments around the world.

DATA SOURCES

Analysis of the prophylaxis protocols in the English literature: An analytical and narrative review of literature concerning DVT prophylaxis protocols in Neurosurgery have been conducted by a PubMed search (back to 1978).

DATA EXTRACTION

80 abstracts were reviewed, and 74 articles were extracted.

DATA ANALYSIS

The majority of DVT seems to develop within the first week after a neurosurgical procedure, and a linear correlation between the duration of surgery and DVT occurrence has been highlighted. The incidence of DVT seems greater for cranial (7.7%) than spinal procedures (1.5%). Although intermittent pneumatic compression (IPC) devices provided adequate reduction of DVT/PE in some cranial and combined cranial/spinal series, low-dose subcutaneous unfractionated heparin (UFH) or low molecular-weight heparin (LMWH) further reduced the incidence, not always of DVT, but of PE. Nevertheless, low-dose heparin-based prophylaxis in cranial and spinal series risks minor and major postoperative haemorrhages: 2-4% in cranial series, 3.4% minor and 3.4% major haemorrhages in combined cranial/spinal series, and a 0.7% incidence of major/minor haemorrhages in spinal series.

CONCLUSION

This analysis showed that currently most of the articles are represented by case series and case reports. As long as clear guidelines will not be defined and universally applied to this diverse group of patients, any prophylaxis for DVT and PE should be tailored to the individual patient with cautious assessment of benefits versus risks.

The postoperative venous thromboembolism (TREVO) study - risk and case mortality by surgical specialty

INTRODUCTION AND OBJECTIVES

Venous thromboembolism, risk of which is increased in surgical patients, is a preventable cause of morbidity and death. The primary objective of this study was to estimate the incidence of symptomatic postoperative venous thromboembolism in adults at a tertiary university hospital, overall and by surgical specialty. The secondary objective was to analyze severity of and mortality from thromboembolic events.

METHODS

We performed a retrospective study to identify cases of in-hospital postoperative venous thromboembolism, encoded by the International Classification of Diseases, Ninth Revision, according to the Joint Commission International criteria. Adult patients admitted for surgery in 2008-2012 were included.

RESULTS

Among 67 635 hospitalizations, 90 cases of postoperative symptomatic venous thromboembolism were identified, corresponding to an incidence of 1.33/1000 admissions (95% confidence interval [CI] 1.1-1.6/1000). Neurosurgery had the highest risk (4.07/1000), followed by urological surgery and general surgery (p<0.001). There were 50 cases of pulmonary embolism, 11 of which were fatal. Of the 90 cases, 12.2% occurred under neuraxial anesthesia and 55.1% in patients with American Society of Anesthesiology III physical status. At least 37.7% of patients with events received a prophylactic dose of injectable anticoagulant postoperatively. The overall risk decreased from 2008 to 2012. Venous thromboembolism-associated mortality during hospitalization was 21.1% (95% CI 13.6-30.4).

CONCLUSIONS

The incidence of postoperative symptomatic venous thromboembolism was 1.33/1000. Neurosurgery showed the greatest risk. Mortality was 21.1%.

Risk of deep venous thrombosis in elective neurosurgical procedures: a prospective, Doppler ultrasound-based study in children 12 years of age or younger

OBJECTIVE The risk of venous thromboembolism (VTE) from deep venous thrombosis (DVT) is significant in neurosurgical patients. VTE is considered a leading cause of preventable hospital deaths and preventing DVT is a closely monitored quality metric, often tied to accreditation, hospital ratings, and reimbursement. Adult protocols include prophylaxis with anticoagulant medications. Children's hospitals may adopt adult protocols, although the incidence of DVT and the risk or efficacy of treatment is not well defined. The incidence of DVT in children is likely less than in adults, although there is very little prospectively collected information. Most consider the risk of DVT to be extremely low in children 12 years of age or younger. However, this consideration is based on tradition and retrospective reviews of trauma databases. In this study, the authors prospectively evaluated pediatric patients undergoing a variety of elective neurosurgical procedures and performed Doppler ultrasound studies before and after surgery. METHODS A total of 100 patients were prospectively enrolled in this study. All of the patients were between the ages of 1 month and 12 years and were undergoing elective neurosurgical procedures. The 91 patients who completed the protocol received a bilateral lower-extremity Doppler ultrasound examination within 48 hours prior to surgery. Patients did not receive either medical or mechanical DVT prophylaxis during or after surgery. The ultrasound examination was repeated within 72 hours after surgery. An independent, board-certified radiologist evaluated all sonograms. We prospectively collected data, including potential risk factors, details of surgery, and details of the clinical course. All patients were followed clinically for at least 1 year. RESULTS There was no clinical or ultrasound evidence of DVT or VTE in any of the 91 patients. There was no clinical evidence of VTE in the 9 patients who did not complete the protocol. CONCLUSIONS In this prospective study, no DVTs were found in 91 patients evaluated by ultrasound and 9 patients followed clinically. While the study is underpowered to give a definitive incidence, the data suggest that the risk of DVT and VTE is very low in children undergoing elective neurosurgical procedures. Prophylactic protocols designed for adults may not apply to pediatric patients. Clinical trial registration no.: NCT02037607 (clinicaltrials.gov).

Impact of practice change in reducing venous thromboembolism in neurocritical overweight patients: 2008-2014

Publications regarding early initiating venous thromboembolism (VTE) prophylaxis have been available since the early 1990s. These recommendations became available in current guidelines on and after 2012. The purpose of this study is to review the practice change in reducing the incidence of VTE in brain injury patients from 2008 to 2014. This was a single-center, retrospective, observational, cohort study. Data was extracted from our data base that included patients over 100 kg from January 2008 to August 2014. Included were all patients admitted with a primary diagnosis of acute brain and spinal injury to neurocritical care unit. Clinical endpoints examined were incidence of bleeding and VTE. A total of 509 patients who met the inclusion criteria were divided into two groups: The previous group (n = 212) included patients from 2008 to 2010, and the recent group (n = 297) included patients from 2011 to 2014. The time for initiating VTE prophylaxis from admission was (median, IQR) 73 h (37-140) vs. 34 h (20-46); p < 0.01. There were no differences in major and minor bleeding complications. Discontinuation of VTE prophylaxis for association with progressive bleeding was not documented in any of the study patients. The incidence of VTE was 10 % (22/212) vs. 5 % (15/297); p = 0.02. In hospital LOS in days was 16 (10-26) vs. 7 (4-15); P < 0.01. In multivariable logistic regression analysis, only the time of the initiation VTE prophylaxis after admission was significantly associated with the occurrence of VTE (median, IQR) 70 h (37-158) vs. 36 h (20-63); OR 1.004, 95 % CI 1.001-1.007; P < 0.01. In this 6-year review of data, early initiation of VTE prophylaxis has decreased the incidence of VTE without clinically documented bleeding complications.

Risk factors for deep venous thrombosis of lower limbs in postoperative neurosurgical patients

Objectives:

To detect the risk factors for deep venous thrombosis (DVT) in patients after neurosurgery.

Methods:

Three hundred and seventy-six patients treated in the department of neurosurgery of our hospital from February 2013 to November 2015 were reviewed retrospectively. The clinical data including age, gender, hospital stay, operation time, occupation type, hypertension, coronary heart disease, diabetes, smoking status, drinking status, postoperative exercises, malignant tumor, and postoperative hormone or dehydrating agent were collected.

Results:

In this study, 52 patients were included in the DVT group and 295 patients in the Non-DVT group. There was significant difference in age, hypertension, occupation type, malignant tumors, operation time, smoking status, and postoperative exercises between the two groups (p<0.05). However, there was no significant difference in gender, drinking status, coronary heart disease, diabetes, hospital stay, and postoperative hormone or dehydrating agent (p>0.05). In multivariate analysis, age, malignant tumor, hypertension were independent risk factors, while physical labour and postoperative exercises were protective factor for DVT.

Conclusion:

The postoperative patients with older age, malignant tumor or hypertension should be paid high attention to prevent DVT, and postoperative exercises should be selected as precautionary measures.

Venous Thromboembolism and Malignant Brain Tumors: A Review

The incidence of venous thromboembolism (VTE) in patients with primary brain tumors varies be tween 1 and 60%. This variability in incidence is due to study differences in (a) methods of diagnosis of VTE— i.e., diagnosis at autopsy or clinical diagnosis; (b) amount of time from surgery to VTE diagnosis; (c) proportion of patients receiving deep venous thrombosis (DVT) pro phylaxis ; (d) clinical risk factors associated with VTE, such as paresis, prior thrombotic disease, and chemother apy; and (e) tumor location and histology. The etiology of VTE in patients with primary brain tumors is unknown. The preoperative hemostatic abnormalities noted in clin ical studies have been most consistent with compensated disseminated intravascular coagulation (DIC). These ab normalities, however, appear to be of little predictive value for the subsequent development of VTE. Studies involving brain tumor tissue or cell cultures have impli cated factors released by the tumor or surrounding neural tissue that activate the coagulation system or inhibit fi brinolysis. Recommendations for VTE prophylaxis in clude (a) earliest possible ambulation; (b) intermittent pneumatic compression in all nonambulatory patients preoperatively and postoperatively; and (c) s.c. heparin in high-risk patients. The role of low-molecular-weight heparin in VTE prophylaxis has not been established. Patients with malignant brain tumors can be safely anti coagulated with heparin and warfarin if these agents are carefully monitored. Of 197 patients in seven series who received anticoagulants, only 5 (2.5%) had intracranial bleeding. Vena caval filters and thrombectomy are rarely required. Thrombolytic therapy is contraindicated. Key Words: Venous thromboembolism—Deep venous throm bosis—Malignant brain tumors.

Radiosurgery following Embolisation and/or Surgery of Brain AVM's

A series of 45 patients who have undergone combined treatment for cerebral arteriovenous malformations (AVM's) is presented. All patients underwent additional radiosurgery after endovascular and/or surgical treatment. Stereotactic radiosurgical treatment using the Gamma knife has been available in our institution since 1992.

The treatment strategy for brain AVM's has changed since that time. The possibility for total cure of partially embolised AVM's, where other treatment options had been exhausted, increased with adjunctive radiosurgery. Complex or giant AVM's in eloquent areas can now be treated using radiosurgery after embolisation and/or microsurgery, with minor risk of neurological deficit.

In all 45 patients treated since September 1992 at the University of Vienna, embolisation was performed to reduce the size of the nidus in order to facilitate surgical resection or radiosurgical treatment.

In 37 patients radiosurgery was performed after endovascular treatment only, and in 8 patients radiosurgery was performed after embolisation and surgery. All AVM's were classified according to Spetzler's Grading System. 31 patients (68.9%) were classified as Grade 3 or 4. Two patients (4.5%) were classified as Grade 5.

In a mean follow up time of 16 months (range 2–40), there were 15 complete obliterations and 2 patients with unexpected residual AVM after two years.

Of patients who required staged radiosurgical therapy, 12 have been followed for less than two years after their final procedure. In an additional 12 patients the follow-up period is less than 12 months. 4 patients were lost to follow up. There is a morbidity of 8.8% and no mortality in this patient group.

High dose subcutaneous unfractionated heparin for prevention of venous thromboembolism in overweight neurocritical care patients

Timing and dosing of chemical venous thromboembolism (VTE) prophylaxis in brain injury is controversial. Risk of bleeding while using high dose unfractionated heparin (UFH) in overweight patients to prevent VTE is also unknown. The purpose of this study was to describe the use of subcutaneous heparin 7500 units for VTE prophylaxis in overweight patients. This was a retrospective study comparing patients over 100 kg who received either 7500 units Q8 h (n = 141) (high dose group, HDG), or 5000 units Q8 h (n = 257) (traditional dose group, TDG), of UFH subcutaneously. Both groups had similar rates of bleeding complications. The incidence of drop in hemoglobin by two points in any 24 h was 14 % (20/141) HDG versus 11 % (28/257) TDG; P = 0.33. Hemoglobin drop by two points from baseline was 57 % (81/141) HDG versus 51 % (132/257) TDG; P = 0.24. The need for pRBC transfusion was 26 % (36/141) HDG versus 20 % (52/257) TDG; P = 0.22. An increase in aPTT from baseline by two times was 4 % (5/141) HDG versus 4 % (9/257) TDG, P = 0.59. Discontinuation of heparin therapy for association with progressive bleeding was not documented in any patients. No differences in minor bleeding complications were observed. There was no difference in the incidence of VTE: 5.7 % (8/141) HDG versus 9.3 % (24/257) TDG; P = 0.2. In univariate and multivariable logistic regression analysis, only the time of the initiation of heparin after admission was associated with the occurrence of VTE (median, IQR) 46 h (17-86) HDG versus 105 h (56-167) TDG; OR 1.2 (1.1-1.3); P < 0.001. High dose subcutaneous UFH was not associated with an increased risk of bleeding, nor did it decrease the incidence of VTE in overweight patients.

Clinical features and risk factor analysis for lower extremity deep venous thrombosis in Chinese neurosurgical patients

Background:

Deep venous thrombosis (DVT) contributes significantly to the morbidity and mortality of neurosurgical patients; however, no data regarding lower extremity DVT in postoperative Chinese neurosurgical patients have been reported.

Materials and Methods:

From January 2012 to December 2013, 196 patients without preoperative DVT who underwent neurosurgical operations were evaluated by color Doppler ultrasonography and D-dimer level measurements on the 3^rd, 7^th, and 14^th days after surgery. Follow-up clinical data were recorded to determine the incidence of lower extremity DVT in postoperative neurosurgical patients and to analyze related clinical features. First, a single factor analysis, Chi-square test, was used to select statistically significant factors. Then, a multivariate analysis, binary logistic regression analysis, was used to determine risk factors for lower extremity DVT in postoperative neurosurgical patients.

Results:

Lower extremity DVT occurred in 61 patients, and the incidence of DVT was 31.1% in the enrolled Chinese neurosurgical patients. The common symptoms of DVT were limb swelling and lower extremity pain as well as increased soft tissue tension. The common sites of venous involvement were the calf muscle and peroneal and posterior tibial veins. The single factor analysis showed statistically significant differences in DVT risk factors, including age, hypertension, smoking status, operation time, a bedridden or paralyzed state, the presence of a tumor, postoperative dehydration, and glucocorticoid treatment, between the two groups (P < 0.05). The binary logistic regression analysis showed that an age greater than 50 years, hypertension, a bedridden or paralyzed state, the presence of a tumor, and postoperative dehydration were risk factors for lower extremity DVT in postoperative neurosurgical patients.

Conclusions:

Lower extremity DVT was a common complication following craniotomy in the enrolled Chinese neurosurgical patients. Multiple factors were identified as predictive of DVT in neurosurgical patients, including the presence of a tumor, an age greater than 50 years, hypertension, and immobility.

Cutoff values of plasma d-dimer level in patients with diagnosis of the venous thromboembolism after elective spinal surgery

Study Design

A prospective clinical study.

Purpose

Our objective in the present study was twofold. First, we sought to evaluate the relationship between postoperative venous thromboembolism (VTE) development and concentration of D-dimer to determine the cutoff value in patients who underwent elective spinal surgery. Second, we identified the predictive risk factors for postoperative VTE.

Overview of Literature

VTE affects the general health of patients and may even cause death. Since the complications of VTE are difficult to predict, the safest and most cost effective diagnostic method should be used in order to confirm a suspected VTE event after spinal surgery.

Methods

This study was performed on 97 patients who underwent elective spinal surgery. The D-dimer assay was carried out on the day before surgery, and on days 1, 3, and 10 following surgery. VTE occurrence and D-dimer levels were compared between the VTE and the control groups.

Results

Four patients (4.1%) were diagnosed with deep vein thrombosis and one patient (1%) was diagnosed with a pulmonary embolism. The optimum D-dimer cutoff value on day 3 following surgery in the VTE group was determined to be more than 2.1 µg/mL with a sensitivity of 100% and a specificity of 80.7%. Moreover, the duration of postoperative recumbency was a significant risk factor for the development of VTE in this study.

Conclusions

We have demonstrated that postoperative D-dimer measurements in patients who underwent elective spinal surgery can provide a complementary diagnostic screening for VTE during the first week after surgery.

Predictors of neurological deficit after endovascular treatment of cerebral arteriovenous malformations and functional repercussions in prospective follow-up

Endovascular therapy is a well-established approach to the treatment of cerebral arteriovenous malformations (AVMs). The objective of this study was to determine the predictive factors of neurological deficit following endovascular procedures. Seventy-one patients with cerebral AVMs who underwent 147 embolization sessions from 2006 to 2011 were followed up prospectively (average 31.1 ± 17.5 months). Functional neurological condition was documented by means of the modified Rankin scale. Factors found to be predictors of neurological deficit were the partial obstruction of drainage veins (OR = 197.6; IC = 2.76 -1416.0; P = 0.015), a positive result in the Propofol test (OR = 50.2; IC = 6.18 - 566.5; P = 0.000), AVM diameter under 3 cm (OR = 21.3; IC: 1.71 - 265.6; P = 0.018), the presence of intranidal aneurysms (OR = 11.2; IC = 1.09 - 114.2; P = 0.042), the absence of post-procedure hypotension (OR = 10.2; IC = 1.35 - 77.7; P = 0.003), deep venous drainage (OR = 7.14; IC = 1.15 - 44.4; P = 0.035), and devascularization in excess of 40% per session (OR = 3.3; IC = 1.11 - 16.8; P = 0.056). Fifty-six patients (78.9%) did not experience changes in their neurological condition after the treatment and 13 patients (18.3%) showed a new neurological deficit related to the treatment; 95.8 % of the patients did not show significant long-term incapacity. Partial obstruction of drainage veins, small AVMs, intranidal aneurysms, faulty hemodynamic control and extensive devascularization were found to be predictors of neurological deficit. A significant number of patients with neurological deficit improved in the long term.