Venous thromboembolic events in patients undergoing craniotomy for tumor resection: incidence, predictors, and review of literature

OBJECTIVE

The authors sought to investigate the incidence and predictors of venous thromboembolic events (VTEs) after craniotomy for tumor resection, which are not well established, and the efficacy of and risks associated with VTE chemoprophylaxis, which remains controversial.

METHODS

The authors investigated the incidence of VTEs in a consecutive series of patients presenting to the authors' institution for resection of an intracranial lesion between 2012 and 2017. Information on patient and tumor characteristics was collected and independent predictors of VTEs were determined using stepwise multivariate logistic regression analysis. Review of the literature was performed by searching MEDLINE using the keywords "venous thromboembolism," "deep venous thrombosis," "pulmonary embolism," "craniotomy," and "brain neoplasms."

RESULTS

There were 1622 patients included for analysis. A small majority of patients were female (52.6%) and the mean age of the cohort was 52.9 years (SD 15.8 years). A majority of intracranial lesions were intraaxial (59.3%). The incidence of VTEs was 3.0% and the rates of deep venous thromboses and pulmonary emboli were 2.3% and 0.9%, respectively. On multivariate analysis, increasing patient age (unit OR 1.02, 95% CI 1.00-1.05; p = 0.018), history of VTE (OR 7.26, 95% CI 3.24-16.27; p < 0.001), presence of motor deficit (OR 2.64, 95% CI 1.43-4.88; p = 0.002), postoperative intracranial hemorrhage (OR 4.35, 95% CI 1.51-12.55; p < 0.001), and prolonged intubation or reintubation (OR 3.27, 95% CI 1.28-8.32; p < 0.001) were independently associated with increased odds of a VTE. There were 192 patients who received VTE chemoprophylaxis (11.8%); the mean postoperative day of chemoprophylaxis initiation was 4.6 (SD 3.8). The incidence of VTEs was higher in patients receiving chemoprophylaxis than in patients not receiving chemoprophylaxis (8.3% vs 2.2%; p < 0.001). There were 30 instances of clinically significant postoperative hemorrhage (1.9%), with only 1 hemorrhage occurring after initiation of VTE chemoprophylaxis (0.1%).

CONCLUSIONS

The study results show the incidence and predictors of VTEs after craniotomy for tumor resection in this patient population. The incidence of VTE within this cohort appears low and comparable to that observed in other institutional series, despite the lack of routine prophylactic anticoagulation in the postoperative setting.

A machine learning approach to predict early outcomes after pituitary adenoma surgery

OBJECTIVEPituitary adenomas occur in a heterogeneous patient population with diverse perioperative risk factors, endocrinopathies, and other tumor-related comorbidities. This heterogeneity makes predicting postoperative outcomes challenging when using traditional scoring systems. Modern machine learning algorithms can automatically identify the most predictive risk factors and learn complex risk-factor interactions using training data to build a robust predictive model that can generalize to new patient cohorts. The authors sought to build a predictive model using supervised machine learning to accurately predict early outcomes of pituitary adenoma surgery.METHODSA retrospective cohort of 400 consecutive pituitary adenoma patients was used. Patient variables/predictive features were limited to common patient characteristics to improve model implementation. Univariate and multivariate odds ratio analysis was performed to identify individual risk factors for common postoperative complications and to compare risk factors with model predictors. The study population was split into 300 training/validation patients and 100 testing patients to train and evaluate four machine learning models using binary classification accuracy for predicting early outcomes.RESULTSThe study included a total of 400 patients. The mean ± SD patient age was 53.9 ± 16.3 years, 59.8% of patients had nonfunctioning adenomas and 84.7% had macroadenomas, and the mean body mass index (BMI) was 32.6 ± 7.8 (58.0% obesity rate). Multivariate odds ratio analysis demonstrated that age < 40 years was associated with a 2.86 greater odds of postoperative diabetes insipidus and that nonobese patients (BMI < 30) were 2.2 times more likely to develop postoperative hyponatremia. Using broad criteria for a poor early postoperative outcome-major medical and early surgical complications, extended length of stay, emergency department admission, inpatient readmission, and death-31.0% of patients met criteria for a poor early outcome. After model training, a logistic regression model with elastic net (LR-EN) regularization best predicted early postoperative outcomes of pituitary adenoma surgery on the 100-patient testing set-sensitivity 68.0%, specificity 93.3%, overall accuracy 87.0%. The receiver operating characteristic and precision-recall curves for the LR-EN model had areas under the curve of 82.7 and 69.5, respectively. The most important predictive variables were lowest perioperative sodium, age, BMI, highest perioperative sodium, and Cushing's disease.CONCLUSIONSEarly postoperative outcomes of pituitary adenoma surgery can be predicted with 87% accuracy using a machine learning approach. These results provide insight into how predictive modeling using machine learning can be used to improve the perioperative management of pituitary adenoma patients.

Outpatient and inpatient readmission rates of 3- and 4-level anterior cervical discectomy and fusion surgeries

OBJECTIVE

With the costs related to the United States medical system constantly rising, efforts are being made to turn traditional inpatient procedures into outpatient same-day surgeries. In this study the authors looked at the various comorbidities and perioperative complications and their impact on readmission rates of patients undergoing outpatient versus inpatient 3- and 4-level anterior cervical discectomy and fusion (ACDF).

METHODS

This was a retrospective study of 337 3- and 4- level ACDF procedures in 332 patients (5 patients had both primary and revision surgeries that were included in this total of 337 procedures) between May 2012 and June 2017. In total, 331 procedures were analyzed, as 6 patients were lost to follow-up. Outpatient surgery was performed for 299 procedures (102 4-level procedures and 197 3-level procedures), and inpatient surgery was performed for 32 procedures (11 4-level procedures and 21 3-level procedures). Age, sex, comorbidities, number of fusion levels, pain level, and perioperative complications were compared between both cohorts.

RESULTS

Analysis was performed for 331 3- and 4-level ACDF procedures done at 6 different hospitals. The overall 30-day readmission rate was 1.2% (outpatient 3 [1.0%] vs inpatient 1 [3.1%], p = 0.847). Outpatients had increased readmission risk, with comorbidities of coronary artery disease (OR 1.058, p = 0.039), autoimmune disease (OR 1.142, p = 0.006), diabetes (OR 1.056, p = 0.001), and chronic kidney disease (OR 0.933, p = 0.035). Perioperative complications of delirium (OR 2.709, p < 0.001) and surgical site infection (OR 2.709, p < 0.001) were associated with increased risk of 30-day hospital readmission in outpatients compared to inpatients.

CONCLUSIONS

This study demonstrates the safety and effectiveness of 3- and 4-level ACDF surgery, although various comorbidities and perioperative complications may lead to higher readmission rates. Patient selection for outpatient 3- and 4-level ACDF cases might play a role in the safety of performing these procedures in the ambulatory setting, but further studies are needed to accurately identify which factors are most pertinent for appropriate selection.

Long-term outcomes following deep brain stimulation for Parkinson's disease

OBJECTIVE: Deep brain stimulation (DBS) is an effective treatment for several movement disorders, including Parkinson's disease (PD). While this treatment has been available for decades, studies on long-term patient outcomes have been limited. Here, the authors examined survival and long-term outcomes of PD patients treated with DBS. METHODS: The authors conducted a retrospective analysis using medical records of their patients to identify the first 400 consecutive patients who underwent DBS implantation at their institution from 1999 to 2007. The medical record was used to obtain baseline demographics and neurological status. The authors performed survival analyses using Kaplan-Meier estimation and multivariate regression using Cox proportional hazards modeling. Telephone surveys were used to determine long-term outcomes. RESULTS: Demographics for the cohort of patients with PD (n = 320) were as follows: mean age of 61 years, 70% male, 27% of patients had at least 1 medical comorbidity (coronary artery disease, congestive heart failure, diabetes mellitus, atrial fibrillation, or deep vein thrombosis). Kaplan-Meier survival analysis on a subset of patients with at least 10 years of follow-up (n = 200) revealed a survival probability of 51% (mean age at death 73 years). Using multivariate regression, the authors found that age at implantation (HR 1.02, p = 0.01) and male sex (HR 1.42, p = 0.02) were predictive of reduced survival. Number of medical comorbidities was not significantly associated with survival (p > 0.5). Telephone surveys were completed by 40 surviving patients (mean age 55.1 ± 6.4 years, 72.5% male, 95% subthalamic nucleus DBS, mean follow-up 13.0 ± 1.7 years). Tremor responded best to DBS (72.5% of patients improved), while other motor symptoms remained stable. Ability to conduct activities of daily living (ADLs) remained stable (dressing, 78% of patients; running errands, 52.5% of patients) or worsened (preparing meals, 50% of patients). Patient satisfaction, however, remained high (92.5% happy with DBS, 95% would recommend DBS, and 75% felt it provided symptom control). CONCLUSIONS: DBS for PD is associated with a 10-year survival rate of 51%. Survey data suggest that while DBS does not halt disease progression in PD, it provides durable symptomatic relief and allows many individuals to maintain ADLs over long-term follow-up greater than 10 years. Furthermore, patient satisfaction with DBS remains high at long-term follow-up.

Rate of instrumentation changes on postoperative and follow-up radiographs after primary complex spinal fusion (five or more levels) for adult deformity correction

OBJECTIVEIn the United States, healthcare expenditures have been soaring at a concerning rate. There has been an excessive use of postoperative radiographs after spine surgery and this has been a target for hospitals to reduce unnecessary costs. However, there are only limited data identifying the rate of instrumentation changes on radiographs after complex spine surgery involving ≥ 5-level fusions.METHODSThe medical records of 136 adult (≥ 18 years old) patients with spine deformity undergoing elective, primary complex spinal fusion (≥ 5 levels) for deformity correction at a major academic institution between 2010 and 2015 were reviewed. Patient demographics, comorbidities, and intra- and postoperative complication rates were collected for each patient. The authors reviewed the first 5 subsequent postoperative and follow-up radiographs, and determined whether revision of surgery was performed within 5 years postoperatively. The primary outcome investigated in this study was the rate of hardware changes on follow-up radiographs.RESULTSThe majority of patients were female, with a mean age of 53.8 ± 20.0 years and a body mass index of 27.3 ± 6.2 kg/m2 (parametric data are expressed as the mean ± SD). The median number of fusion levels was 9 (interquartile range 7-13), with a mean length of surgery of 327.8 ± 124.7 minutes and an estimated blood loss of 1312.1 ± 1269.2 ml. The mean length of hospital stay was 6.6 ± 3.9 days, with a 30-day readmission rate of 14.0%. Postoperative and follow-up change in stability on radiographs (days from operation) included: image 1 (4.6 ± 9.3 days) 0.0%; image 2 (51.7 ± 49.9 days) 3.0%; image 3 (142.1 ± 179.8 days) 5.6%; image 4 (277.3 ± 272.5 days) 11.3%; and image 5 (463.1 ± 525.9 days) 15.7%. The 3rd year after surgery had the highest rate of hardware revision (5.55%), followed by the 2nd year (4.68%), and the 1st year (4.54%).CONCLUSIONSThis study suggests that the rate of instrumentation changes on radiographs increases over time, with no changes occurring at the first postoperative image. In an era of cost-conscious healthcare, fewer orders for early radiographs after complex spinal fusions (≥ 5 levels) may not impact patient care and can reduce the overall use of healthcare resources.

Factors associated with venous thromboembolic events following ICU admission in patients undergoing spinal surgery: an analysis of 1269 consecutive patients

In BriefIn a retrospective study the authors examined 1269 patients who underwent spinal surgery and were admitted to the intensive care unit (ICU) and identified factors that are associated with venous thromboembolic events (VTEs) in this "high risk" group. Amongst these high-risk factors were: surgeries longer than 4 hours, comorbid disease, patients needing an osteotomy, and patients undergoing spinal stabilization for fractures. Identification of factors that can be optimized prior to surgery will decrease the rates of VTE.

Neuromuscular scoliosis complication rates from 2004 to 2015: a report from the Scoliosis Research Society Morbidity and Mortality database

OBJECTIVE Postoperative complications are one of the most significant concerns in surgeries of the spine, especially in higher-risk cases such as neuromuscular scoliosis. Neuromuscular scoliosis is a classification of multiple diseases affecting the neuromotor system or musculature of patients leading to severe degrees of spinal deformation, disability, and comorbidity, all likely contributing to higher rates of postoperative complications. The objective of this study was to evaluate deformity correction of patients with neuromuscular scoliosis over a 12-year period (2004-2015) by looking at changes in postsurgical complications and management. METHODS The authors queried the Scoliosis Research Society (SRS) Morbidity and Mortality (M&M) database for neuromuscular scoliosis cases from 2004 to 2015. The SRS M&M database is an international database with thousands of self-reported cases by fellowship-trained surgeons. The database has previously been validated, but reorganization in 2008 created less-robust data sets from 2008 to 2011. Consequently, the majority of analysis in this report was performed using cohorts that bookend the 12-year period (2004-2007 and 2012-2015). Of the 312 individual fields recorded per patient, demographic analysis was completed for age, sex, diagnosis, and preoperative curvature. Analysis of complications included infection, bleeding, mortality, respiratory, neurological deficit, and management practices. RESULTS From 2004 to 2015, a total of 29,019 cases of neuromuscular scoliosis were reported with 1385 complications, equating to a 6.3% complication rate when excluding the less-robust data from 2008 to 2011. This study shows a 3.5-fold decrease in overall complication rates from 2004 to 2015. A closer look at complications shows a significant decrease in wound infections (superficial and deep), respiratory complications, and implant-associated complications. The overall complication rate decreased by approximately 10% from 2004-2007 to 2012-2015. CONCLUSIONS This study demonstrates a substantial decrease in complication rates from 2004 to 2015 for patients with neuromuscular scoliosis undergoing spine surgery. Decreases in specific complications, such as surgical site infection, allow us to gauge our progress while observing how trends in management affect outcomes. Further study is needed to validate this report, but these results are encouraging, helping to reinforce efforts toward continual improvement in patient care.

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.

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).

Prophylactic use of intraoperative vancomycin powder and postoperative infection: an analysis of microbiological patterns in 1200 consecutive surgical cases

OBJECTIVE Wound infections following spinal surgery for deformity place a high toll on patients, providers, and the health care system. The prophylactic application of intraoperative vancomycin powder has been shown to lower the infection risk after thoracolumbar decompression and fusion for deformity correction. The purpose of this study was to assess the microbiological patterns of postoperative surgical site infections (SSIs) after prophylactic use of vancomycin powder in adult patients undergoing spinal deformity surgery. METHODS All cases involving adult patients who underwent spinal deformity reconstruction at Duke University Medical Center between 2011 and 2013 with a minimum of 3 months of clinical follow-up were retrospectively reviewed. In all cases included in the study, crystalline vancomycin powder was applied to the surgical bed for infection prophylaxis. Baseline characteristics, operative details, rates of wound infection, and microbiological data for each case were gathered by direct medical record review. RESULTS A total of 1200 consecutive spine operations were performed for deformity between 2011 and 2013. Review of the associated records demonstrated 34 cases of SSI, yielding an SSI rate of 2.83%. The patients' mean age (± SD) was 62.08 ± 14.76 years. The patients' mean body mass index was 30.86 ± 7.15 kg/m², and 29.41% had a history of diabetes. The average dose of vancomycin powder was 1.41 ± 2.77 g (range 1-7 g). Subfascial drains were placed in 88% of patients. All SSIs occurred within 30 days of surgery, with deep wound infections accounting for 50%. In 74% of the SSIs cultures were positive, with about half the organisms being gram negative, such as Citrobacter freundii, Proteus mirabilis, Morganella morgani, and Pseudomonas aeruginosa. There were no adverse clinical outcomes related to the local application of vancomycin. CONCLUSIONS Our study suggests that in the setting of prophylactic vancomycin powder use, the preponderance of SSIs are caused by gram-negative organisms or are polymicrobial. Further randomized control trials of prophylactic adjunctive measures are warranted to help guide the choice of empirical antibiotic therapy while awaiting culture data.

Safety and cost efficiency of a restrictive transfusion protocol in patients with traumatic brain injury

OBJECTIVE Blood loss and moderate anemia are common in patients with traumatic brain injury (TBI). However, despite evidence of the ill effects and expense of the transfusion of packed red blood cells, restrictive transfusion practices have not been universally adopted for patients with TBI. At a Level I trauma center, the authors compared patients with TBI who were managed with a restrictive (target hemoglobin level > 7 g/dl) versus a liberal (target hemoglobin level > 10 g/dl) transfusion protocol. This study evaluated the safety and cost-efficiency of a hospital-wide change to a restrictive transfusion protocol. METHODS A retrospective analysis of patients with TBI who were admitted to the intensive care unit (ICU) between January 2011 and September 2015 was performed. Patients < 16 years of age and those who died within 24 hours of admission were excluded. Demographic data and injury characteristics were compared between groups. Multivariable regression analyses were used to assess hospital outcome measures and mortality rates. Estimates from an activity-based cost analysis model were used to detect changes in cost with transfusion protocol. RESULTS A total of 1565 patients with TBI admitted to the ICU were included in the study. Multivariable analysis showed that a restrictive transfusion strategy was associated with fewer days of fever (p = 0.01) and that patients who received a transfusion had a larger fever burden. ICU length of stay, ventilator days, incidence of lung injury, thromboembolic events, and mortality rates were not significantly different between transfusion protocol groups. A restrictive transfusion protocol saved approximately $115,000 annually in hospital direct and indirect costs. CONCLUSIONS To the authors' knowledge, this is the largest study to date to compare transfusion protocols in patients with TBI. The results demonstrate that a hospital-wide change to a restrictive transfusion protocol is safe and cost-effective in patients with TBI.

Indications, technique, and safety profile of insular stereoelectroencephalography electrode implantation in medically intractable epilepsy

OBJECTIVE Insular epilepsy is relatively rare; however, exploring the insular cortex when preoperative workup raises the suspicion of insular epilepsy is of paramount importance for accurate localization of the epileptogenic zone and achievement of seizure freedom. The authors review their clinical experience with stereoelectroencephalography (SEEG) electrode implantation in patients with medically intractable epilepsy and suspected insular involvement. METHODS A total of 198 consecutive cases in which patients underwent SEEG implantation with a total of 1556 electrodes between June 2009 and April 2013 were reviewed. The authors identified patients with suspected insular involvement based on seizure semiology, scalp EEG data, and preoperative imaging (MRI, PET, and SPECT or magnetoencephalography [MEG]). Patients with at least 1 insular electrode based on the postoperative 3D reconstruction of CT fused with the preoperative MRI were included. RESULTS One hundred thirty-five patients with suspected insular epilepsy underwent insular implantation of a total of 303 electrodes (1-6 insular electrodes per patient) with a total of 562 contacts. Two hundred sixty-eight electrodes (88.5%) were implanted orthogonally through the frontoparietal or temporal operculum (420 contacts). Thirty-five electrodes (11.5%) were implanted by means of an oblique trajectory either through a frontal or a parietal entry point (142 contacts). Nineteen patients (14.07%) had insular electrodes placed bilaterally. Twenty-three patients (17.04% of the insular implantation group and 11.6% of the whole SEEG cohort) were confirmed by SEEG to have ictal onset zones in the insula. None of the patients experienced any intracerebral hemorrhage related to the insular electrodes. After insular resection, 5 patients (33.3%) had Engel Class I outcomes, 6 patients (40%) had Engel Class II, 3 patients (20%) had Engel Class III, and 1 patient (6.66%) had Engel Class IV. CONCLUSIONS Insula exploration with stereotactically placed depth electrodes is a safe technique. Orthogonal electrodes are implanted when the hypothesis suggests opercular involvement; however, oblique electrodes allow a higher insular sampling rate.

Depression as an independent predictor of postoperative delirium in spine deformity patients undergoing elective spine surgery

OBJECTIVE Depression is the most prevalent affective disorder in the US, and patients with spinal deformity are at increased risk. Postoperative delirium has been associated with inferior surgical outcomes, including morbidity and mortality. The relationship between depression and postoperative delirium in patients undergoing spine surgery is relatively unknown. The aim of this study was to determine if depression is an independent risk factor for the development of postoperative delirium in patients undergoing decompression and fusion for deformity. METHODS The medical records of 923 adult patients (age ≥ 18 years) undergoing elective spine surgery at a single major academic institution from 2005 through 2015 were reviewed. Of these patients, 255 (27.6%) patients had been diagnosed with depression by a board-certified psychiatrist and constituted the Depression group; the remaining 668 patients constituted the No-Depression group. Patient demographics, comorbidities, and intra- and postoperative complication rates were collected for each patient and compared between groups. The primary outcome investigated in this study was rate of postoperative delirium, according to DSM-V criteria, during initial hospital stay after surgery. The association between depression and postoperative delirium rate was assessed via multivariate logistic regression analysis. RESULTS Patient demographics and comorbidities other than depression were similar in the 2 groups. In the Depression group, 85.1% of the patients were taking an antidepressant prior to surgery. There were no significant between-group differences in intraoperative variables and rates of complications other than delirium. Postoperative complication rates were also similar between the cohorts, including rates of urinary tract infection, fever, deep and superficial surgical site infection, pulmonary embolism, deep vein thrombosis, urinary retention, and proportion of patients transferred to the intensive care unit. In total, 66 patients (7.15%) had an episode of postoperative delirium, with depressed patients experiencing approximately a 2-fold higher rate of delirium (10.59% vs 5.84%). In a multivariate logistic regression analysis, depression was an independent predictor of postoperative delirium after spine surgery in spinal deformity patients (p = 0.01). CONCLUSIONS The results of this study suggest that depression is an independent risk factor for postoperative delirium after elective spine surgery. Further studies are necessary to understand the effects of affective disorders on postoperative delirium, in hopes to better identify patients at risk.

Incidence and risk factors for preoperative deep venous thrombosis in 314 consecutive patients undergoing surgery for spinal metastasis

OBJECTIVE The authors of this study aimed to identify the incidence of and risk factors for preoperative deep venous thrombosis (DVT) in patients undergoing surgical treatment for spinal metastases. METHODS Univariate analysis of patient age, sex, ethnicity, laboratory values, comorbidities, preoperative ambulatory status, histopathological classification, spinal level, and surgical details was performed. Factors significantly associated with DVT univariately were entered into a multivariate logistic regression model. RESULTS The authors identified 314 patients, of whom 232 (73.9%) were screened preoperatively for a DVT. Of those screened, 22 (9.48%) were diagnosed with a DVT. The screened patients were older (median 62 vs 55 years, p = 0.0008), but otherwise similar in baseline characteristics. Nonambulatory status, previous history of DVT, lower partial thromboplastin time, and lower hemoglobin level were statistically significant and independent factors associated with positive results of screening for a DVT. Results of screening were positive in only 6.4% of ambulatory patients in contrast to 24.4% of nonambulatory patients, yielding an odds ratio of 4.73 (95% CI 1.88-11.90). All of the patients who had positive screening results underwent preoperative placement of an inferior vena cava filter. CONCLUSIONS Patients requiring surgery for spinal metastases represent a population with unique risks for venous thromboembolism. This study showed a 9.48% incidence of DVT in patients screened preoperatively. The highest rates of preoperative DVT were identified in nonambulatory patients, who were found to have a 4-fold increase in the likelihood of harboring a DVT. Understanding the preoperative thrombotic status may provide an opportunity for early intervention and risk stratification in this critically ill population.

A systematic multidisciplinary initiative for reducing the risk of complications in adult scoliosis surgery

OBJECTIVE Systematic multidisciplinary approaches to improving quality and safety in complex surgical care have shown promise. Complication rates from complex spine surgery range from 10% to 90% for all surgeries, and the overall mortality rate is 1%-4%. These rates suggest the need for improved perioperative complex spine surgery processes designed to minimize risk and improve quality. METHODS The Group Health Research Institute and Virginia Mason Medical Center implemented a systematic multidisciplinary protocol, the Seattle Spine Team Protocol, in 2010. This protocol involves the following elements: 1) a comprehensive multidisciplinary conference including clinicians from neurosurgery, anesthesia, orthopedics, internal medicine, behavioral health, and nursing, collaboratively deciding on each patient's suitability for surgery; 2) a mandatory patient education course that reviews the risks of surgery, preparation for the surgery, and postoperative care; 3) a dual-attending-surgeon approach involving 1 neurosurgeon and 1 orthopedic spine surgeon; 4) a dedicated specialist complex spine anesthesia team; and 5) rigorous intraoperative monitoring of a patient's blood loss and coagulopathy. The authors identified 71 patients who underwent complex spine surgery involving fusion of 6 or more levels before implementation of the protocol (surgery between 2008 and 2010) and 69 patients who underwent complex spine surgery after the implementation of the protocol (2010 and 2012). All patient demographic variables, including age, sex, body mass index, smoking status, diagnosis of diabetes and/or osteoporosis, previous surgery, and the nature of the spinal deformity, were comprehensively assessed. Also comprehensively assessed were surgical variables, including operative time, number of levels fused, and length of stay. The authors assessed overall complication rates at 30 days and 1 year and detailed deaths, cardiovascular events, infections, instrumentation failures, and CSF leaks. Chi-square and Wilcoxon rank-sum tests were used to assess differences in patient characteristics for patients with a procedure in the preimplementation period from those in the postimplementation period under a Poisson distribution model. RESULTS Patients who underwent surgery after implementation of the Seattle Spine Team Protocol had a statistically significant reduction (relative risk 0.49 [95% CI 0.30-0.78]) in all measured complications, including cardiovascular events, wound infections, other perioperative infections, and implant failures within 30 days after surgery; the analysis was adjusted for age and Charlson comorbidity score. A trend toward fewer deaths in this group was also found. CONCLUSIONS This type of systematic quality improvement strategy can improve quality and patient safety and might be applicable to other complex surgical disciplines. Implementation of these strategies in the treatment of adult spinal deformity will likely lead to better patient outcomes.

Heparin-induced thrombocytopenia presenting as unilateral lower limb paralysis following lumbar spine surgery: case report

Heparin-induced thrombocytopenia (HIT) is a state of thrombocytopenia with a paradoxically elevated thrombotic potential after exposure to heparin. Severe cases can present with multiorgan involvement with direct and secondary effects. Although HIT has been reported following other surgeries, to the authors' knowledge there has not been a report of HIT after spinal surgery. The present case details the course of a patient who underwent elective lumbar surgery followed by delayed presentation of shortness of breath due to multiple pulmonary embolisms and right lower-extremity paralysis due to extensive iliofemoral clot burden with acute compartment syndrome. The patient was treated with intravenous argatroban for extensive thrombosis and also required open thrombectomy and fasciotomies for treatment of compartment syndrome. Although the patient eventually experienced motor recovery, residual sensory deficits persisted at last follow-up. In this report, the pathophysiology, clinical presentation, and treatment of HIT are reviewed.

Patient and operative factors associated with complications following adolescent idiopathic scoliosis surgery: an analysis of 36,335 patients from the Nationwide Inpatient Sample

OBJECTIVE The aim of this study was to investigate the incidence of and factors associated with complications following idiopathic scoliosis surgery in adolescents. METHODS The Nationwide Inpatient Sample database was used to identify patients 10-18 years of age who had undergone spinal fusion for adolescent idiopathic scoliosis (AIS) from 2002 to 2011. Twenty-three unique in-hospital postoperative complications, including death, were examined. A series of logistic regressions was used to determine if any demographic, comorbid, or surgical parameter was associated with complication development. Results of multiple logistic regression analyses were reported as odds ratios with 95% confidence intervals. All analyses were performed after the application of discharge weights to produce national estimates. RESULTS A total of 36,335 patients met the study inclusion criteria, 7.6% of whom (95% CI 6.3%-8.9%) developed at least one in-hospital complication. The 3 most common complications were respiratory failure (3.47%), reintubation (1.27%), and implant related (1.14%). Major complications such as death, pancreatitis, disseminated intravascular coagulation, visual loss, spinal cord injury, cardiac arrest, sepsis, nerve root injury, deep vein thrombosis, pulmonary embolism, shock, malignant hyperthermia, myocardial infarction, and iatrogenic stroke each had an incidence ≤ 0.2%. On multiple logistic regression analysis, an increasing age (OR 0.80) was associated with significantly lower odds of complication development; patients who were male (OR 1.80) or who had anemia (OR 2.10), hypertension (OR 2.51), or hypothyroidism (OR 2.27) or underwent revision procedures (OR 5.55) were at a significantly increased risk for complication development. The rates of postoperative complications for posterior, anterior, and combined approaches were 6.7%, 10.0%, and 19.8%, respectively (p < 0.001). Length of fusion (< 8 vs ≥ 8 levels) was not associated with complication development (p = 0.311). CONCLUSIONS Analysis of 36,335 patients who had undergone surgery for AIS revealed that younger patients, male patients, patients with a history of anemia, hypertension, or hypothyroidism, as well as those undergoing revision or anterior or combined approaches may have higher rates of postoperative complications. However, the overall complication rate was low (7.6%), and major complications had a rate ≤ 0.2% for each event. These findings suggest that surgery for AIS remains relatively safe, and future prospective investigations may further help to decrease the postoperative morbidity rate.

Risk factors for unplanned readmission within 30 days after pediatric neurosurgery: a nationwide analysis of 9799 procedures from the American College of Surgeons National Surgical Quality Improvement Program

OBJECTIVE Hospital readmission rate is increasingly used as a quality outcome measure after surgery. The purpose of this study was to establish, using a national database, the baseline readmission rates and risk factors for patient readmission after pediatric neurosurgical procedures. METHODS The American College of Surgeons National Surgical Quality Improvement Program-Pediatric database was queried for pediatric patients treated by a neurosurgeon between 2012 and 2013. Procedures were categorized by current procedural terminology (CPT) code. Patient demographics, comorbidities, preoperative laboratory values, operative variables, and postoperative complications were analyzed via univariate and multivariate techniques to find associations with unplanned readmissions within 30 days of the primary procedure. RESULTS A total of 9799 cases met the inclusion criteria, 1098 (11.2%) of which had an unplanned readmission within 30 days. Readmission occurred 14.0 ± 7.7 days postoperatively (mean ± standard deviation). The 4 procedures with the highest unplanned readmission rates were CSF shunt revision (17.3%; CPT codes 62225 and 62230), repair of myelomeningocele > 5 cm in diameter (15.4%), CSF shunt creation (14.1%), and craniectomy for infratentorial tumor excision (13.9%). The lowest unplanned readmission rates were for spine (6.5%), craniotomy for craniosynostosis (2.1%), and skin lesion (1.0%) procedures. On multivariate regression analysis, the odds of readmission were greatest in patients experiencing postoperative surgical site infection (SSI; deep, organ/space, superficial SSI, and wound disruption: OR > 12 and p < 0.001 for each). Postoperative pneumonia (OR 4.294, p < 0.001), urinary tract infection (OR 4.262, p < 0.001), and sepsis (OR 2.616, p = 0.006) also independently increased the readmission risk. Independent patient risk factors for unplanned readmission included Native American race (OR 2.363, p = 0.019), steroid use > 10 days (OR 1.411, p = 0.010), oxygen supplementation (OR 1.645, p = 0.010), nutritional support (OR 1.403, p = 0.009), seizure disorder (OR 1.250, p = 0.021), and longer operative time (per hour increase, OR 1.059, p = 0.029). CONCLUSIONS This study may aid in identifying patients at risk for unplanned readmission following pediatric neurosurgery, potentially helping to focus efforts at lowering readmission rates, minimizing patient risk, and lowering costs for health care systems.

Morphometrics as a predictor of perioperative morbidity after lumbar spine surgery

OBJECT Improved objective assessments of perioperative risk after spine surgery are necessary to decrease postoperative morbidity and mortality rates. Morphometric analysis has proven utility in predicting postoperative morbidity and mortality in surgical disciplines. The aim of the present study was to evaluate whether morphometrics can be applied to the cases of patients undergoing lumbar spine surgery. METHODS The authors performed a retrospective review of the perioperative course of 395 patients who underwent lumbar surgery at their institution from 2013 to 2014. Preoperative risk factors such as age, diabetes, smoking, coronary artery disease, and body mass index (BMI) were recorded. Preoperative MRI was used to measure the psoas muscle area at the L-4 vertebra and paraspinal muscle area at the T-12 vertebra. Primary outcomes included unplanned return to the operating room, 30- and 90-day readmissions, surgical site infection, wound dehiscence, new neurological deficit, deep vein thrombosis, pulmonary embolism, myocardial infarction, urinary tract infection, urinary retention, hospital-acquired pneumonia, stroke, and prolonged stay in the intensive care unit. RESULTS The overall rate of adverse events was 30%, the most common event being urinary retention (12%). Greater age (p = 0.015) and tobacco usage (p = 0.026) were both significantly associated with complications for all patients, while diabetes, coronary artery disease, and high BMI were not. No surgery-related characteristics were associated with postoperative morbidity, including whether surgery required instrumentation, whether it was a revision, or the number of vertebral levels treated. Using multivariate regression analysis, male and female patients with the lowest psoas tertile had an OR of 1.70 (95% CI 1.04-2.79, p = 0.035) for having postoperative complications. Male patients in the lowest psoas tertile had an OR of 2.42 (95% CI 1.17-5.01, p = 0.016) for having a postoperative complication. The paraspinal muscle groups did not provide any significant data for postoperative morbidity, even after multivariate analysis. CONCLUSIONS The morphometric measurement of psoas muscle size may be a sensitive predictive tool compared with other risk factors for perioperative morbidity in male patients undergoing lumbar surgery.

Early venous thromboembolism chemoprophylaxis in combat-related penetrating brain injury

OBJECTIVE Traumatic brain injury (TBI) is independently associated with deep vein thrombosis (DVT) and pulmonary embolism (PE). Given the numerous studies of civilian closed-head injury, the Brain Trauma Foundation recommends venous thromboembolism chemoprophylaxis (VTC) after severe TBI. No studies have specifically examined this practice in penetrating brain injury (PBI). Therefore, the authors examined the safety and effectiveness of early VTC after PBI with respect to worsening intracranial hemorrhage and DVT or PE. METHODS The Kandahar Airfield neurosurgery service managed 908 consults between January 2010 and March 2013. Eighty of these were US active duty members with PBI, 13 of whom were excluded from analysis because they presented with frankly nonsurvivable CNS injury or they died during initial resuscitation. This is a retrospective analysis of the remaining 67 patients. RESULTS Thirty-two patients received early VTC and 35 did not. Mean time to the first dose was 24 hours. Fifty-two patients had blast-related PBI and 15 had gunshot wounds (GSWs) to the head. The incidence of worsened intracranial hemorrhage was 16% after early VTC and 17% when it was not given, with the relative risk approaching 1 (RR = 0.91). The incidence of DVT or PE was 12% after early VTC and 17% when it was not given (RR = 0.73), though this difference was not statistically significant. CONCLUSIONS Early VTC was safe with regard to the progression of intracranial hemorrhage in this cohort of combat-related PBI patients. Data in this study suggest that this intervention may have been effective for the prevention of DVT or PE but not statistically significantly so. More research is needed to clarify the safety and efficacy of this practice.

Rate of perioperative neurological complications after surgery for cervical spinal cord stimulation

OBJECTIVE Cervical spinal cord stimulation (cSCS) is used to treat pain of the cervical region and upper extremities. Case reports and small series have shown a relatively low risk of complication after cSCS, with only a single reported case of perioperative spinal cord injury in the literature. Catastrophic cSCS-associated spinal cord injury remains a concern as a result of underreporting. To aid in preoperative counseling, it is necessary to establish a minimum rate of spinal cord injury and surgical complication following cSCS. METHODS The Nationwide Inpatient Sample (NIS) is a stratified sample of 20% of all patient discharges from nonfederal hospitals in the United States. The authors identified discharges with a primary procedure code for spinal cord stimulation (ICD-9 03.93) associated with a primary diagnosis of cervical pathology from 2002 to 2011. They then analyzed short-term safety outcomes including the presence of spinal cord injury and neurological, medical, and general perioperative complications and compared outcomes using univariate analysis. RESULTS Between 2002 and 2011, there were 2053 discharges for cSCS. The spinal cord injury rate was 0.5%. The rates of any neurological, medical, and general perioperative complications were 1.1%, 1.4%, and 11.7%, respectively. There were no deaths. CONCLUSIONS In the largest series of cSCS, the risk of spinal cord injury was higher than previously reported (0.5%). Nonetheless, this procedure remains relatively safe, and physicians may use these data to corroborate the safety of cSCS in an appropriately selected patient population. This may become a key treatment option in an increasingly opioid-dependent, aging population.

Lumbar spine surgery positioning complications: a systematic review

OBJECT There are a variety of surgical positions that provide optimal exposure of the dorsal lumbar spine. These include the prone, kneeling, knee-chest, knee-elbow, and lateral decubitus positions. All are positions that facilitate exposure of the spine. Each position, however, is associated with an array of unique complications that result from excessive pressure applied to the torso or extremities. The authors reviewed clinical studies reporting complications that arose from positioning of the patient during dorsal exposures of the lumbar spine. METHODS MEDLINE, Scopus, and Web of Science database searches were performed to find clinical studies reporting complications associated with positioning during lumbar spine surgery. For articles meeting inclusion criteria, the following information was obtained: publication year, study design, sample size, age, operative time, type of surgery, surgical position, frame or table type, complications associated with positioning, time to first observed complication, long-term outcomes, and evidence-based recommendations for complication avoidance. RESULTS Of 3898 articles retrieved from MEDLINE, Scopus, and Web of Science, 34 met inclusion criteria. Twenty-four studies reported complications associated with use of the prone position, and 7 studies investigated complications after knee-chest positioning. Complications associated with the knee-elbow, lateral decubitus, and supine positions were each reported by a single study. Vision loss was the most commonly reported complication for both prone and knee-chest positioning. Several other complications were reported, including conjunctival swelling, Ischemic orbital compartment syndrome, nerve palsies, thromboembolic complications, pressure sores, lower extremity compartment syndrome, and shoulder dislocation, highlighting the assortment of possible complications following different surgical positions. For prone-position studies, there was a relationship between increased operation time and position complications. Only 3 prone-position studies reported complications following procedures of less than 120 minutes, 7 studies reported complications following mean operative times of 121-240 minutes, and 9 additional studies reported complications following mean operative times greater than 240 minutes. This relationship was not observed for knee-chest and other surgical positions. CONCLUSIONS This work presents a systematic review of positioning-related complications following prone, knee-chest, and other positions used for lumbar spine surgery. Numerous evidence-based recommendations for avoidance of these potentially severe complications associated with intraoperative positioning are discussed. This investigation may serve as a framework to educate the surgical team and decrease rates of intraoperative positioning complications.

Unplanned readmissions and survival following brain tumor surgery

OBJECT

Research on readmissions has been influenced by efforts to reduce hospital cost and avoid penalties stipulated by the Centers for Medicare and Medicaid Services. Less emphasis has been placed on understanding these readmissions and their impact on patient outcomes. This study 1) delineates reasons for readmission, 2) explores factors associated with readmissions, and 3) describes their impact on the survival of glioblastoma patients.

METHODS

The authors conducted a retrospective review of 362 cases involving patients with glioblastoma undergoing biopsy or tumor resection at their institution between 2003 and 2011. Reasons for re-hospitalization were characterized according to whether or not they were related to surgery and considered preventable. Multivariate analyses were conducted to identify the effect of readmission on survival and determine factors associated with re-hospitalizations.

RESULTS

Twenty-seven (7.5%) of 362 patients experienced unplanned readmissions within 30 days of surgery. Six patients (22.2%) were readmitted by Day 7, 14 (51.9%) by Day 14, and 20 (74.1%) by Day 21. Neurological, infectious, and thromboembolic complications were leading reasons for readmission, accounting for, respectively, 37.0%, 29.6%, and 22.2% of unplanned readmissions. Twenty-one (77.8%) of the 27 readmissions were related to surgery and 19 (70.4%) were preventable. The adjusted hazard ratio of mortality associated with a readmission was 2.03 (95% CI 1.3-3.1). Higher-functioning patients (OR 0.96, 95% CI 0.9-1.0) and patients discharged home (OR 0.21, 95% CI 0.1-0.6) were less likely to get readmitted.

CONCLUSIONS

An overwhelming fraction of documented unplanned readmissions were considered preventable and related to surgery. Patients who were readmitted to the hospital within 30 days of surgery had twice the risk of mortality compared with patients who were not readmitted.

Race against the clock: overcoming challenges in the management of anticoagulant-associated intracerebral hemorrhage

Patients receiving anticoagulation therapy who present with any type of intracranial hemorrhage--including subdural hematoma, epidural hematoma, subarachnoid hemorrhage, and intracerebral hemorrhage (ICH)--require urgent correction of their coagulopathy to prevent hemorrhage expansion, limit tissue damage, and facilitate surgical intervention as necessary. The focus of this review is acute ICH, but the principles of management for anticoagulation-associated ICH (AAICH) apply to patients with all types of intracranial hemorrhage, whether acute or chronic. A number of therapies--including fresh frozen plasma (FFP), intravenous vitamin K, activated and inactivated prothrombin complex concentrates (PCCs), and recombinant activated factor VII (rFVIIa)--have been used alone or in combination to treat AAICH to reverse anticoagulation, help achieve hemodynamic stability, limit hematoma expansion, and prepare the patient for possible surgical intervention. However, there is a paucity of high-quality data to direct such therapy. The use of 3-factor PCC (activated and inactivated) and rFVIIa to treat AAICH constitutes off-label use of these therapies in the United States. However, in April 2013, the US Food and Drug Administration (FDA) approved Kcentra (a 4-factor PCC) for the urgent reversal of vitamin K antagonist (VKA) anticoagulation in adults with acute major bleeding. Plasma is the only other product approved for this use in the United States. (1) Inconsistent recommendations, significant barriers (e.g., clinician-, therapy-, or logistics-based barriers), and a lack of approved treatment pathways in some institutions can be potential impediments to timely and evidence-based management of AAICH with available therapies. Patient assessment, therapy selection, whether to use a reversal or factor repletion agent alone or in combination with other agents, determination of site-of-care management, eligibility for neurosurgery, and potential hematoma evacuation are the responsibilities of the neurosurgeon, but ultimate success requires a multidisciplinary approach with consultation from the emergency department (ED) physician, pharmacist, hematologist, intensivist, neurologist, and, in some cases, the trauma surgeon.