Incidence and risk factors for postoperative ileus following anterior, posterior, and circumferential lumbar fusion.

BACKGROUND CONTEXT: Postoperative ileus is a known complication of surgery. The incidence and risk factors for ileus after lumbar fusion surgery is not well characterized. PURPOSE: To determine rates of postoperative ileus, a population-based database was analyzed to identify incidence, mortality, and risk factors associated with anterior (ALF), posterior (PLF), and combined anterior/posterior (APLF) lumbar fusions. STUDY DESIGN: This was a retrospective database analysis. PATIENT SAMPLE: The sample consisted of 220,522 patients from the Nationwide Inpatient Sample (NIS) database. OUTCOME MEASURES: Outcome measures were incidence of postoperative ileus, length of stay (LOS), in-hospital costs, and mortality. METHODS: Data from the NIS were obtained from 2002 to 2009. Patients undergoing ALF, PLF, and APLF for degenerative pathologies were identified and the incidence of postoperative ileus was assessed. Patient demographics, Charlson comorbidity index (CCI), LOS, costs, and mortality were assessed. SPSS v.20 was used to detect statistical differences between groups and perform logistic regression analyses to identify independent predictors of postoperative ileus. A p value less than .001 denoted significance. RESULTS: A total of 220,522 lumbar fusions were identified in the United States from 2002 to 2009. There were 19,762 ALFs, 182,801 PLFs, and 17,959 APLFs. The incidence of postoperative ileus was increased in ALFs over PLFs (74.9 vs. 26.0 per 1,000; p<.001). Within PLF and APLF groups, CCI scores were increased in the presence of postoperative ileus (p<.001). Across cohorts, patients with postoperative ileus demonstrated greater LOS and costs (p<.001). PLF-treated patients with postoperative ileus demonstrated increased mortality (p<.001). Independent predictors of postoperative ileus included male gender, 3+ fusion levels, alcohol abuse, anemia, fluid/electrolyte disorders, and weight loss (p<.001). CONCLUSIONS: The results of our study demonstrate increased incidence of postoperative ileus associated with anterior approaches for lumbar fusion. Across cohorts, postoperative ileus was associated with increased LOS and costs. To determine the mortality and resource use associated with postoperative ileus, we recommend preoperatively identifying and treating modifiable risk factors, especially when an anterior approach is used.

Incidence and risk factors for postoperative delirium after lumbar spine surgery.

STUDY DESIGN: Retrospective database analysis. OBJECTIVE: A population-based database was analyzed to characterize the incidence, hospital costs, mortality, and risk factors associated with postoperative delirium after lumbar decompression (LD) and lumbar fusion (LF) surgical procedures. SUMMARY OF BACKGROUND DATA: Postoperative delirium is a common complication after surgery in the elderly that leads to increased hospitalization, cost, and other adverse outcomes. The incidence of delirium after lumbar spine surgery has not been discussed in this literature. METHODS: Data from the Nationwide Inpatient Sample were obtained from 2002-2009. Patients undergoing LD or LF for degenerative pathologies were identified. Patient demographics, comorbidities, length of stay, discharge disposition, costs, and mortality were assessed. SPSS version 20 was used for statistical analysis using independent T tests for discrete variables and χ2 tests for categorical data. Logistic regression was performed to identify independent predictors of delirium. A P value of less than 0.001 was used to denote significance. RESULTS: A total of 578,457 LDs and LFs were identified in the United States from 2002-2009. Of these, 292,177 were LDs and 286,280 were LFs. The overall incidence of delirium was 8.4 events per 1000 cases. Patients undergoing LF had a statistically greater incidence of delirium than patients undergoing LD (11.8 vs. 5.0 per 1000; P < 0.001). Patients experiencing delirium were significantly older and more likely to be female than nonaffected patients (P < 0.001). Patients with delirium in both cohorts demonstrated significantly greater comorbidities, length of stay, greater costs, and more frequent discharge to skilled nursing facilities (P < 0.001). The presence of delirium in LD-treated patients was associated with an increased mortality rate (6.1 vs. 0.8 per 1000; P < 0.001). Logistic regression demonstrated that independent predictors of delirium included older age (≥65 yr), alcohol/drug abuse, depression, psychotic disorders, neurological disorders, deficiency anemia, fluid/electrolyte disorders, and weight loss. CONCLUSION: The results of our study demonstrated an overall incidence of 8.4 events per 1000 lumbar spine surgical procedures. Overall analysis demonstrated an increased incidence of delirium in older females with greater comorbid conditions. Delirium was found to be associated with increased length of stay, costs, and mortality in all patients undergoing lumbar spine surgery. We recommend that physicians put greater effort into recognizing risk factors of delirium and diagnosing it in a timely manner to mitigate its effects. LEVEL OF EVIDENCE: 3.

Incidence and mortality of cardiac events in lumbar spine surgery.

STUDY DESIGN: Retrospective national database analysis. OBJECTIVE: A population-based database was analyzed to characterize the incidence, mortality, and associated risk factors for cardiac events in lumbar spine surgery. SUMMARY OF BACKGROUND DATA: Cardiac events are a leading cause of perioperative mortality in spinal surgery. The incidence of these complications after lumbar surgery is not well characterized on a national level. METHODS: Data from the Nationwide Inpatient Sample was obtained from 2002 to 2009. Patients undergoing lumbar decompression or lumbar fusion for degenerative etiologies were identified. Patient demographics, incidence of cardiac complications, comorbidities, and mortality were assessed. Statistical analysis was performed using Student t test for discrete variables and χ test for categorical data. Logistic regression was used to identify independent predictors for cardiac complications. RESULTS: A total of 578,457 lumbar spine procedures were identified in the Nationwide Inpatient Sample from 2002 to 2009. The overall incidence of cardiac complications was 6.7 per 1000 cases. Cardiac events occurred more frequently in the lumbar fusion group, with a rate of 9.3 per 1000 cases, than in the lumbar decompression group, with a rate of 4.0 per 1000 (P < 0.0005). Patients with cardiac events were significantly older than patients without complications by 9.4 years (P < 0.0005). Patients with cardiac complications had statistically increased hospitalizations, costs, and mortality when a cardiac event was present (P < 0.0005). Logistic regression analysis demonstrated independent predictors for cardiac events to include age 65 years or older, acute blood loss anemia, and several comorbidities. CONCLUSION: Our results demonstrated an overall incidence of 6.7 cardiac complications per 1000 lumbar spine surgical procedures from 2002 to 2009. Patients undergoing lumbar fusion were more likely to experience cardiac events than lumbar decompression patients. Cardiac events tend to occur in patients with noted risk factors and result in increased hospitalizations, costs, and mortality. On the basis of these findings, we think that patients with specified risk factors should be monitored closely and medically optimized in the perioperative period.

Incidence, risk factors, and mortality associated with aspiration in cervical spine surgery.

STUDY DESIGN: Retrospective national database analysis. OBJECTIVE: A population-based database was analyzed to characterize the incidence, mortality, and associated risk factors for aspiration pneumonia in cervical spine surgery. SUMMARY OF BACKGROUND DATA: Aspiration pneumonia represents a potentially fatal complication of any surgical procedure. The incidence of this complication is not well characterized after cervical spine surgery. METHODS: Data from the Nationwide Inpatient Sample was obtained from 2002-2009. Patients undergoing anterior cervical fusion, posterior cervical fusion, or posterior cervical decompression for radiculopathy and/or myelopathy were identified. Patient demographics, incidence of aspiration, costs, and mortalities were assessed. Statistical analysis was performed using Student t test for discrete variables and χ test for categorical data. Logistic regression was used to identify independent predictors for aspiration. RESULTS: A total of 202,694 patients were identified in the Nationwide Inpatient Sample from 2002 to 2009. Of these, 166,633 were anterior cervical fusions (82.2%), 13,298 were posterior cervical fusions (6.6%), and 22,764 were posterior cervical decompressions (11.2%). The overall incidence of aspiration was 5.3 events per 1000 cases. The greatest incidence was demonstrated in posterior cervical fusion-treated patients with 13.7 per 1000 cases, followed by posterior cervical decompressions with 6.4 per 1000 and anterior cervical fusions with 4.5 per 1000. Patients affected by aspiration were significantly older, more frequently male, and had greater comorbidities than unaffected patients (P < 0.001). Patients diagnosed with aspiration demonstrated significantly greater length of stay, costs, and mortality (P < 0.001). Logistic regression analysis demonstrated independent predictors of aspiration to include advanced age (≥65 yr), male sex, congestive heart failure, coagulopathy, neuropsychiatric disorders, and weight loss (P < 0.001). CONCLUSION: We demonstrated an overall incidence of 5.3 cases of aspiration per 1000 cervical procedures. Patients most commonly affected by aspiration were older males with greater comorbidity. Hospital courses complicated by aspiration had greater length of stay, costs, and mortality. Identification of patients with risk factors for aspiration may assist in early diagnosis and treatment to prevent further morbidity and mortality.

Outcomes of cervical spine surgery in teaching and non-teaching hospitals.

STUDY DESIGN: Retrospective national database analysis. OBJECTIVE: A national population-based database was analyzed to characterize cervical spine procedures performed at teaching and nonteaching hospitals with regards to patient demographics, clinical outcomes/complications, resource use, and costs. SUMMARY OF BACKGROUND DATA: There are mixed reports in the literature regarding the quality and costs of health care provided by teaching hospitals in the United States. However, outcomes of cervical spine surgery based upon teaching status remains largely unknown. METHODS.: Data from the Nationwide Inpatient Sample were obtained from 2002-2009. Patients undergoing elective anterior or posterior cervical fusion, or posterior cervical decompression (i.e., laminoforaminotomy, laminectomy, laminoplasty) for a diagnosis of cervical myelopathy and/or radiculopathy were identified and separated into 2 cohorts (teaching and nonteaching hospitals). Patient demographics, comorbidities, complications, length of hospitalization, costs, and mortality were compared for both groups. Regression analysis was performed to assess independent predictors of mortality. RESULTS: A total of 212,385 cervical procedures were identified from 2002-2009 in the United States, with 54.6% performed at teaching hospitals. More multilevel fusions and posterior approaches were performed in teaching hospitals (P < 0.0005). Patients treated in teaching hospitals trended toward male sex, increased costs, and hospitalizations. Overall, procedure-related complications and inhospital mortality were increased in teaching hospitals. Regression analysis revealed that significant predictors of mortality were age 65 years or more (odds ratio = 3.0) and multiple comorbidities. Teaching status was not a significant predictor of mortality (P = 0.07). CONCLUSION: Patients treated in teaching hospitals for cervical spine surgery demonstrated longer hospitalizations, increased costs, and mortality compared with patients treated in nonteaching hospitals. Incidences of postoperative complications were identified to be higher in teaching hospitals. Possible explanations for these findings are an increased complexity of procedures performed at teaching hospitals. Older age and presence of comorbidities were more significant predictors of inhospital mortality than teaching status. Future studies should identify long-term complications and costs beyond an inpatient setting to assess if differences extend beyond the perioperative period. LEVEL OF EVIDENCE: 4.

Hospital outcomes and complications of anterior and posterior cervical fusion with bone morphogenetic protein.

STUDY DESIGN: Retrospective database analysis. OBJECTIVE: A nationwide population-based database was analyzed to identify the incidence of complications and mortality associated with bone morphogenetic protein (BMP) utilization in cervical spine fusion surgery. SUMMARY OF BACKGROUND DATA: "Off-label" use of BMP as an adjunct in cervical fusions has been associated with increased complication rates in small case series. The incidence of complications with utilization of BMP is not well characterized on a national level. METHODS: Data from the Nationwide Inpatient Sample were obtained for each year from 2002-2009. Patients undergoing anterior cervical fusion (ACF) or posterior cervical fusion for diagnoses of cervical myelopathy and/or radiculopathy were identified and separated into cohorts ("BMP" and "No BMP"). Patient demographics and comorbidities were compared. Complications, length of stay, costs, and mortality rates were assessed. Student t test and χ test were used to assess significant differences. A P value of less than 0.0005 was used to denote significance. RESULTS: A total of 213,421 ACFs and 20,334 posterior cervical fusions were identified from 2002-2009; 6.2% of all ACFs and 12.5% of posterior cervical fusions utilized BMP. Patients receiving BMP in the ACF group were older with greater comorbidities than patients who did not receive BMP (P < 0.0005). Both surgical groups with BMP experienced increased length of stay and costs. Overall complication rates were significantly greater when BMP was utilized in ACFs (P < 0.0005) due to a significantly higher rate of dysphagia (37.2 vs. 22.5 per 1000 cases) (P < 0.0005). CONCLUSION: Our study found that "off-label" use of BMP as an adjunct to cervical fusions was associated with increased rates of dysphagia in ACFs and increased costs for all cervical fusions. Our study does not measure long-term outcomes after discharge; however, the impact of increased inhospital costs, length of stay, and incidence of dysphagia with utilization of BMP should be considered prior to its use in cervical fusions.

Incidence and mortality of perioperative cardiac events in cervical spine surgery.

STUDY DESIGN: Retrospective database analysis. OBJECTIVE: To determine the national incidence, mortality, and risk factors for perioperative cardiac complications associated with cervical spine surgery in the United States. SUMMARY OF BACKGROUND DATA: Perioperative myocardial infarctions and cardiac failure are leading causes of mortality in noncardiac surgery. The incidence of these complications has not been reported in cervical spine surgery. METHODS: Data from the Nationwide Inpatient Sample was obtained from 2002-2009. Patients undergoing anterior or posterior cervical fusion and posterior cervical decompression without fusion for degenerative etiologies were identified. Only elective admissions were included. Incidences of cardiac complications were identified and patient demographics, hospital costs, length of stay, and mortality were compared for each group. Logistic regression was used to identify independent predictors of cardiac complications. RESULTS: A total of 214,900 elective cervical spine procedures were identified in the United States from 2002-2009. Overall, there were 4.0 cardiac events per 1000 cases. For individual procedures, the incidence was 11.6 per 1000 posterior cervical fusions, 5.2 per 1000 posterior cervical decompressions, and 3.2 per 1000 anterior cervical fusions. Patients with cardiac events were statistically older with greater comorbidities (P < 0.0005). Across all cohorts, length of stay increased an additional 4.5 days, hospital costs increased $13,435, and mortality increased from 0.8 to 65.3 deaths per 1000 cases in the presence of a cardiac event (P < 0.0005). Logistic regression analysis demonstrated that independent predictors for cardiac events included age 65 years or more, multilevel fusions, acute blood-loss anemia, congestive heart failure, fluid/electrolyte disorders, and pulmonary circulation disorders. CONCLUSION: Our results demonstrate an overall incidence of 4.0 cardiac events per 1000 cervical spine surgical procedures. Older patients with greater comorbid risk factors, particularly cardiovascular diseases, were at significantly increased risk for cardiac complications. Due to the large impact cardiac events have on health care utilization and mortality, we recommend thorough risk stratification for older patients undergoing elective cervical spine procedures. LEVEL OF EVIDENCE: 3.

Epidemiological trends in cervical spine surgery for degenerative diseases between 2002 and 2009.

STUDY DESIGN: Retrospective analysis of a population-based database. OBJECTIVE: To investigate national epidemiological trends of cervical spine surgical procedures from 2002-2009. SUMMARY OF BACKGROUND DATA: Anterior cervical fusion (ACF), posterior cervical fusion (PCF), and posterior cervical decompression (PCD) are procedures routinely performed for cervical degenerative pathology. Studies regarding epidemiological trends of these procedures is currently lacking in the literature. METHODS: Data from the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project was obtained for each year between 2002 and 2009. Patients undergoing ACF, PCF, and PCD for the diagnosis of cervical radiculopathy and myelopathy were identified. Demographics, costs, and mortality were assessed in the surgical subgroups. A P value of 0.001 was used to denote significance. RESULTS.: An estimated 1,323,979 cervical spine surgical procedures were performed between 2002 and 2009. There was a significant upward trend in the mean age of patients undergoing cervical spine surgery during this time period. ACF and PCF cohorts demonstrated statistically significant increases in comorbidities and costs from 2002-2009. The PCF group had the greatest mortality, comorbidities, costs, and longest hospitalizations compared with ACF and PCF cohorts across all time periods. CONCLUSION: Our study demonstrates that cervical spine surgical procedures have increased between 2002 and 2009 (P = 0.001). The primary increase in volume is due to the increasing number of ACFs. Despite older patients with more comorbidities undergoing ACF and PCF procedures, mortality has not changed. However, this patient population trended significant increases in costs during this time period. We hypothesize that these increased costs are due to an increased comorbidity burden in patients undergoing ACF or PCF. Results of this study can be used to set benchmarks for future epidemiological investigations in cervical spine surgery. 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.

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.