Thromboembolic events and spinal surgery

Cerebral Thromboembolic Events During Anterior Cervical Spine Surgery: Retrospective Case Series Study With Diffusion-Weighted Magnetic Resonance Imaging Follow-up in the Immediate Postoperative Period

Objective

We evaluated the efficacy of diffusion-weighted magnetic resonance imaging (DW-MRI) in detecting perioperative cerebral thromboembolic events after anterior cervical discectomy and fusion (ACDF).

Methods

This retrospective case series included 51 consecutive patients that underwent ACDF. To assess baseline presence of plaque or stenosis, all patients were assessed for risk factors of cerebrovascular events and underwent carotid ultrasound preoperatively and cerebral DW-MRI was performed in all patients postoperatively, with areas of high signal intensity interpreted as a cerebral thromboembolic event.

Results

One male patient who underwent a C4/5 ACDF had a focal diffusion abnormality on DW-MRI concerning for cerebral thromboembolic events in the right posterior cerebral artery territory. He remained asymptomatic and did not display related neurological symptoms, such as visual deficits.

Conclusion

Asymptomatic cerebral thromboembolic events can be detected by DW-MRI after ACDF. The incidence of such events remains very rare despite the direct manipulation and associated alteration of common carotid artery flow dynamics.

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.

The Role of Minimally Invasive Techniques in Scoliosis Correction Surgery

OBJECTIVE

Recently, minimally invasive surgery (MIS) has been included among the treatment modalities for scoliosis. However, literature comparing MIS to open surgery for scoliosis correction is limited. The objective of this study was to compare outcomes for scoliosis correction patients undergoing MIS versus open approach.

METHODS

We retrospectively collected data on demographics, procedure characteristics, and outcomes for 207 consecutive scoliosis correction surgeries at our institution between 2009 and 2015.

RESULTS

MIS patients had lower number of levels fused (p < 0.0001), shorter surgeries (p = 0.0023), and shorter overall lengths of stay (p < 0.0001), were less likely to be admitted to the ICU (p < 0.0001), and had shorter ICU stays (p = 0.0015). On multivariable regression, number of levels fused predicted selection for MIS procedure (p = 0.004), and multiple other variables showed trends toward significance. Age predicted ICU admission and VTE. BMI predicted any VTE, and DVT specifically. Comorbid disease burden predicted readmission, need for transfusion, and ICU admission. Number of levels fused predicted prolonged surgery, need for transfusion, and ICU admission.

CONCLUSIONS

Patients undergoing MIS correction had shorter surgeries, shorter lengths of stay, and shorter and fewer ICU stays, but there was a significant selection effect. Accounting for other variables, MIS did not independently predict any of the outcomes.

Thromboembolic Disease after Cervical Spine Surgery: A Review of 5,405 Surgical Procedures and Matched Cohort Analysis

STUDY DESIGN

Retrospective matched cohort analysis.

OBJECTIVE

The majority of the literature on venous thromboembolism (VTE) after spine surgery is limited to studies of thoracolumbar surgery. Less is known regarding the incidence of VTE and associated risk factors following cervical spine surgery.

METHODS

A total of 5,405 patients at our institution underwent cervical diskectomy, laminectomy, corpectomy, laminoplasty, or fusion between 1995 and 2012; 85 of the 5,405 patients (1.57%) suffered either a DVT (55) or pulmonary embolus (51) within 30 days postoperatively. The cases were matched 1:2 to controls based on age, sex, and date of surgery. Data regarding multiple perioperative factors, demographics, and comorbidities was collected.

RESULTS

Several risk factors were identified for VTE. Significant medical comorbidities included chronic venous insufficiency (odds ratio [OR] = 3.40), atrial fibrillation (OR = 2.69), obesity (OR = 2.67), and ischemic heart disease (OR = 2.18). Staged surgery (OR = 28.0), paralysis (OR = 19.0), combined approach (OR = 7.46), surgery for infection (OR = 18.5), surgery for trauma (OR = 11.1), comorbid traumatic injuries (OR > 10), oncologic procedures (OR = 5.2), use of iliac crest autograft (OR = 4.16), two or more surgical levels (OR = 3.48), blood loss > 300 mL (OR = 1.66), and length of stay 5 days or greater (OR = 3.47) were all found to be risk factors for VTE (p < 0.05) in univariate analysis. Multivariate analysis found staged surgery (OR = 35.7), paralysis (OR = 7.86), and nonelective surgery (OR = 6.29) to be independent risk factors for VTE.

CONCLUSIONS

Although the incidence of VTE following cervical spine surgery is low, we identified several risk factors that may be predictive. More aggressive approaches to prophylaxis and surveillance in certain patient populations may be warranted.

The incidence and mortality of thromboembolic events in lumbar spine surgery

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

A population-based database was analyzed to identify the incidence, risk factors, and mortality associated with thromboembolic events after lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

Pulmonary embolism (PE) and deep vein thrombosis (DVT) are potential complications that may occur after orthopedic procedures. The incidence of these complications is not well characterized after lumbar spine surgery.

METHODS

Data from the Nationwide Inpatient Sample was obtained from 2002-2009. Patients undergoing lumbar decompression (LD), or lumbar fusion (LF) for degenerative conditions were identified. Acute PE and DVT incidences and mortality rates were calculated. Comorbidities were calculated using a modified Charlson Comorbidity Index. Statistical analysis was performed using the Student t test for discrete variables and χ test for categorical data. Logistic regression was used to identify independent predictors of thromboembolic events. A P value of less than or equal to 0.0005 was used to denote statistical significance.

RESULTS

A total 578,457 LDs and LFs were identified from 2002-2009. DVT incidences were 2.4 and 4.3 per 1000 cases in the LD and LF groups, respectively. PE incidences were 1.0 and 2.6 per 1000 cases in the LD and LF groups, respectively. Patients who had undergone LF with thromboembolic events were younger, had fewer comorbidities, and incurred greater costs than patients who had undergone LD. Statistically significant predictors of DVT were pulmonary circulation disorders, coagulopathy, fluid/electrolyte disorders, anemia, obesity, teaching hospital status, and larger hospitals. Predictors for the development of PE were pulmonary circulation disorders, fluid/electrolyte disorders, anemia, black ethnicity and teaching hospital status.

CONCLUSION

Patients undergoing LD or LF are at inherent risk of thromboembolic events. DVT and PE are more common after LF procedures. Preoperative pulmonary circulation disorders, fluid/electrolyte disorders, deficiency anemia, and teaching hospital status were significant risk factors for developing both DVT and PE. Preventive measures in patients at risk may decrease the incidence of thromboembolic events.

LEVEL OF EVIDENCE

4.

The incidence and mortality of thromboembolic events in cervical spine surgery

STUDY DESIGN

Retrospective database analysis.

OBJECTIVE

A nationwide population-based database was analyzed to identify the incidence, risk factors, and mortalities associated with venous thromboembolism (VTE) after cervical spine surgery.

SUMMARY OF BACKGROUND DATA

Pulmonary embolism (PE) and deep vein thrombosis (DVT) are potential complications that may occur after orthopedic procedures. Incidences of these complications are not well characterized after cervical spine surgery.

METHODS

Data from the Nationwide Inpatient Sample database were obtained from 2002 to 2009. Patients undergoing anterior cervical fusion, posterior cervical fusion, and posterior cervical decompression (i.e., laminoforaminotomy, laminectomy, laminoplasty) for the diagnosis of cervical myelopathy and/or radiculopathy were identified. Incidences of PE and DVT were calculated. Comorbidities were calculated using the modified Charlson Comorbidity Index. Mortality associated with these complications was assessed in the 3 surgical subgroups. Statistical analysis was performed to assess significant differences between groups. Logistic regression was used to identify independent predictors of VTE. A P value of <0.0005 was used to denote significance.

RESULTS

There were 273,396 cervical procedures recorded in the Nationwide Inpatient Sample database from 2002 to 2009. Posterior cervical fusion-treated patients had statistically the highest incidences of DVT and PE, whereas the lowest PE and DVT rates were found in anterior cervical fusion-treated patients (P < 0.0005). All patients with thromboembolic events had significantly increased rates of mortality, hospitalization, and costs compared with patients without VTE across all procedural groups. Logistic regression analysis demonstrated statistically significant predictors of VTE to be male sex, pulmonary circulation disorders, fluid/electrolyte disorders, and teaching-hospital status.

CONCLUSION

Thromboembolic events are potential complications of cervical spine surgery. The highest rates of VTE were identified in those patients undergoing posterior cervical fusion. Regardless of approach, DVT and PEs resulted in increased mortality rates and hospitalization. We recommend a thorough preoperative assessment to identify patients at risk for VTE and treat accordingly to decrease the incidence of these thromboembolic events.