Treatment Outcomes in Spinal Metastatic Disease With Indeterminate Stability.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purpose of this study was to compare outcomes between different treatment modalities for metastatic disease with indeterminate instability (Spinal Instability Neoplastic Score [SINS] 7-12). METHODS: We retrospectively reviewed neurologically intact patients treated for spinal metastatic disease with a SINS of 7 to 12. The cohort was stratified by treatment approach: external beam radiation therapy alone (EBRT), surgery + EBRT (S+E), and cement augmentation + EBRT (K+E). Kaplan-Meier analysis was used to assess differences in length of survival (LOS) and ability to ambulate at time of death. Multivariate analysis was performed to assess adjusted LOS and ability to ambulate at time of death. RESULTS: The cohort included 211 patients, S+E (n = 57), EBRT (n = 128), and K+E (n = 27). In the S+E group, the median LOS was 430 days, which was statistically longer than the median LOS for the EBRT group (121 days) and the K+E group (169 days). In the S+E group, 52 patients (91.2%) and in the K+E group 24 patients (92.3%) retained the ability to ambulate at their time of death compared to 99 patients (77.3%) of the EBRT patients (P = .01). The overall rate of revision treatment at the spinal level initially treated was 17.5%, S+E (15.8%), EBRT (20.3%), and K+E (7.7%). CONCLUSIONS: The length of survival, ability to maintain ambulatory ability, and revision treatment rates were all improved following surgical management and radiation therapy compared to radiation therapy alone. The authors' conclusion from these results are that patients with indeterminate spinal instability should be discussed in a multidisciplinary setting for the need of spinal stabilization in addition to radiation therapy.

Does facility volume influence survival in patients with primary malignant bone tumors of the vertebral column? A comparative cohort study.

BACKGROUND CONTEXT: Facility volume has been correlated with survival in many cancers. This relationship has not been established in primary malignant bone tumors of the vertebral column (BTVC). PURPOSE: To investigate whether facility patient volume is associated with overall survival in patients with primary malignant BTVCs. STUDY DESIGN: Retrospective comparative cohort. PATIENT SAMPLE: Adult patients with chordomas, chondrosarcomas, or osteosarcomas of the mobile spine. OUTCOME MEASURES: Five-year survival. METHODS: We retrospectively analyzed 733 patients with primary malignant BTVCs in the national cancer database from 2004 through 2015. Univariate and multivariate analyses were used to correlate specific outcome measures with facility volume. Volume was stratified based on cumulative martingale residuals to determine the inflection point of negative to positive impact on survival based on the patient cohort. Long-term survival was compared between patients treated at high and low volume using the Kaplan-Meier method. Only patients with malignant primary tumors were considered eligible for inclusion; patients with incomplete treatment data or benign tumors were excluded. RESULTS: Patients treated at high-volume centers (HVCs) were younger (p=.0003) and more likely to be insured (p<.0001). There were no significant differences in tumor characteristics. Patients treated at high-volume facilities had improved 5-year survival of 71% versus 58% at low-volume centers (p<.0001). Patients treated at HVCs were more likely to receive surgical treatment (91% vs. 80%, p<.0001); if surgery was performed, they were more likely to undergo an en bloc resection (48% vs. 30%, p<.0001). However, there were no differences in margin status or utilization of radiotherapy or chemotherapy between HVCs and low-volume centers. In a multivariate analysis, facility volume was independently associated with improved survival overall (HR 0.75 [0.58-0.97], p=.03). CONCLUSIONS: Primary malignant BTVCs are rare, even for HVCs. Despite this, patient survival was significantly improved when treatment was performed at HVCs.

The Role of Radiotherapy for Chordoma Patients Managed With Surgery: Analysis of the National Cancer Database.

STUDY DESIGN: Retrospective review. OBJECTIVE: To determine if adjuvant radiation therapy (RT) improves overall survival (OS) following surgical resection of chordomas. SUMMARY OF BACKGROUND DATA: The role of RT for the treatment of chordomas remains incompletely described. Previous studies have not found adjuvant RT to improve OS, but these studies did not group patients based on surgical margin status or radiation dose or modality. We used the National Cancer Database to investigate the role of RT in chordomas following surgical resection. METHODS: Patients were stratified based on surgical margin status (positive vs. negative). Utilizing the Kaplan-Meier method, OS was compared between treatment modalities (surgical resection alone, therapeutic RT alone, and surgical resection plus therapeutic RT). OS was subsequently compared between patients treated with palliative dose (<40 Gy), low dose (40-65 Gy), and high dose (>65 Gy) RT. Similarly, OS was compared between advanced RT modalities including proton beam therapy (PBT) and intensity-modulated radiation therapy (IMRT), stereotactic radiosurgery (SRS), and external beam radiation therapy (EBRT). A multivariable model was used to determine adjusted variables predictive of mortality. RESULTS: One thousand four hundred seventy eight chordoma patients were identified; skull base (n = 567), sacral (n = 551), and mobile spine (n = 360). Surgical resection and therapeutic adjuvant RT improved 5-year survival in patients with positive surgical margins (82% vs. 71%, P = 0.03). No clear survival benefit was observed with the addition of adjuvant RT in patients with negative surgical margins. High dose RT was associated with improved OS compared with palliative and low dose RT (P < 0.001). Advanced RT techniques and SRS were associated with improved OS compared with EBRT. In the multivariate analysis high dose advanced RT (>65 Gy) was superior to EBRT. CONCLUSION: Patients with positive surgical margins benefit from adjuvant RT. Optimal OS is associated with adjuvant RT administered with advanced techniques and cumulative dose more than 65 Gy. LEVEL OF EVIDENCE: 4.

Epidemiologic and survival trends in adult primary bone tumors of the spine.

BACKGROUND CONTEXT: Malignant primary spinal tumors are rare making it difficult to perform large studies comparing epidemiologic, survival, and treatment trends. We investigated the largest registry of primary bone tumors, the National Cancer Database (NCDB), to compare epidemiologic and survival trends among these tumors. PURPOSE: To use the NCDB to describe current epidemiologic trends, treatment modalities, and overall survival rates in patients with chordomas, osteosarcomas, chondrosarcomas, and Ewing sarcomas of the mobile spine. The secondary objective was to determine prognostic factors that impact overall survival rates. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: A total of 1,011 patients with primary bone tumors of the spine (377 chordomas, 223 chondrosarcomas, 278 Ewing sarcomas, and 133 osteosarcomas). OUTCOME MEASURES: Five-year survival. METHODS: We reviewed the records of 1,011 patients in the NCDB from 2004 through 2015 with histologically confirmed primary osteosarcoma, chondrosarcoma, Ewing sarcoma, or chordoma of the spine. Demographic, clinical, and outcomes data were compiled and compared using chi-squared tests and ANOVA. Long-term survival was compared using the Kaplan-Meier method with statistical comparisons based on the log-rank test. Multivariate analysis was performed to determine survival determinants. RESULTS: Surgical resection was the primary mode of treatment for chondrosarcoma (90%), chordoma (84%), and osteosarcoma (80%). The treatment for Ewing sarcoma was multimodal involving chemotherapy, radiation therapy, and surgical resection. Five-year survival rates varied significantly with chordomas and chondrosarcomas having the greatest survival (70% and 69%), osteosarcomas having the worse survival (38%), and Ewing having intermediate 5-year survival at 62% (overall log-rank p<.0001). Multivariate analysis demonstrated significantly improved 5-year survival rates with younger age at diagnosis, private insurance status, lower comorbidity score, lower tumor grade, smaller tumor size, surgical resection, and negative surgical margin. Radiation therapy only improved survival for Ewing sarcoma. CONCLUSIONS: This study provides the most comprehensive description of the epidemiologic, treatment, and survival trends of primary bone tumors of the mobile spine. Second, patient and tumor characteristics associated with improved 5-year survival were identified using a multivariate model.

Curve Characteristics and Foraminal Dimensions in Patients With Adult Scoliosis and Radiculopathy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To demonstrate a correlation between radiculopathy symptoms, foraminal morphology, and curve types. SUMMARY OF BACKGROUND DATA: Patients with degenerative scoliosis frequently present with foraminal stenosis and radiculopathy, the origin of which is not well understood. METHODS: A total of 48 patients (384 foraminas) were included: 14 with low back pain (B); 16 with femoral nerve pain (F); and 18 with sciatic nerve pain (S). The symptomatic foramen of groups F and S were compared with asymptomatic foramina. Alignment was measured from standardized radiographs; 3D-CT reconstructions were used to measure foraminal height and area. Data are presented as mean±SD. The χ, t test, and Pearson coefficients were calculated; as well as interobserver and intraobserver reproducibility (Cohen κ). RESULTS: Seventeen of the 18 patients with sciatic nerve pain (S) presented foraminal stenosis (<40 mm) at the concavity of the fractional curve distal to the main lumbar structural curve. The symptomatic foramina were significantly smaller in height (7.8±2.5 vs. 12.1±3.1 mm, P<0.0001) and area (30.1±14.3 vs. 57.6±28.7 mm, P<0.0001) compared with asymptomatic foramen; 7/7 patients with femoral nerve pain (F) and lumbar structural curves (apex L3 or lower) had foraminal stenosis at the concavity of the fractional curve. Eight of the 9 patients with femoral nerve pain (F) and thoracic, thoracolumbar, or lumbar (apex L2 or higher) curves, presented foraminal stenosis in the concavity of the caudal fractional curve. The symptomatic foraminal spaces were significantly smaller in height (9.2±3.2 vs. 12.1±3.1 mm, P<0.0001) and area (30.1±15.2 vs. 57.6±28.7 mm, P<0.0001). Foraminal height correlated with foraminal area (r=0.68-0.85; P<0.0001). Interobserver agreement was between 0.6092 and 0.8679. CONCLUSIONS: A correlation between curve types and symptomatic foraminal stenosis exists. Adult scoliosis patients with sciatic nerve pain typically present with foraminal stenosis at the concavity of the caudal fractional curve. Similarly, patients with femoral nerve pain present with foraminal stenosis at the concavity of the caudal fractional curve when the main structural curve is thoracic, thoracolumbar, or lumbar (apex L2 or higher).

A Comparative Analysis Among the SRS M&M, NIS, and KID Databases for the Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVES: A growing number of publications have utilized the Scoliosis Research Society (SRS) Morbidity and Mortality (M&M) database, but none have compared it to other large databases. The objective of this study was to compare SRS complications with those in administrative databases. SUMMARY OF BACKGROUND DATA: The Nationwide Inpatient Sample (NIS) and Kid's Inpatient Database (KID) captured a greater number of overall complications while the SRS M&M data provided a greater incidence of spine-related complications following adolescent idiopathic scoliosis (AIS) surgery. Chi-square was used to obtain statistical significance, with p < .05 considered significant. METHODS: The SRS 2004-2007 (9,904 patients), NIS 2004-2007 (20,441 patients) and KID 2003-2006 (10,184 patients) databases were analyzed for AIS patients who underwent fusion. Comparable variables were queried in all three databases, including patient demographics, surgical variables, and complications. RESULTS: Patients undergoing AIS in the SRS database were slightly older (SRS 14.4 years vs. NIS 13.8 years, p < .0001; KID 13.9 years, p < .0001) and less likely to be male (SRS 18.5% vs. NIS 26.3%, p < .0001; KID 24.8%, p < .0001). Revision surgery (SRS 3.3% vs. NIS 2.4%, p < .0001; KID 0.9%, p < .0001) and osteotomy (SRS 8% vs. NIS 2.3%, p < .0001; KID 2.4%, p < .0001) were more commonly reported in the SRS database. The SRS database reported fewer overall complications (SRS 3.9% vs. NIS 7.3%, p < .0001; KID 6.6%, p < .0001). However, when respiratory complications (SRS 0.5% vs. NIS 3.7%, p < .0001; KID 4.4%, p < .0001) were excluded, medical complication rates were similar across databases. In contrast, SRS reported higher spine-specific complication rates. Mortality rates were similar between SRS versus NIS (p = .280) and SRS versus KID (p = .08) databases. CONCLUSIONS: There are similarities and differences between the three databases. These discrepancies are likely due to the varying data-gathering methods each organization uses to collect their morbidity data. LEVEL OF EVIDENCE: Level IV.

Abnormally High Dislocation Rates of Total Hip Arthroplasty After Spinal Deformity Surgery.

BACKGROUND: The purpose of this study was to determine the prevalence of concurrent spinopelvic fusion and THA and identify the risk of THA dislocation in patients with concurrent spinopelvic fusion. METHODS: We retrospectively reviewed an institutional database of spinal deformity patients and the Humana Inc data set to identify patients with concurrent THA and spinopelvic fusion. The prevalence of concurrent THA and spinopelvic fusion was identified, as was the risk of dislocation for all cohorts. RESULTS: Of 328 patients with spinopelvic fusions at our institution, 15 patients (4.6%) were found to have concurrent THA. Similarly, within the Humana database among 1049 patients with spinopelvic fusion, 4.6% had a concurrent THA. Among the 58,692 THA patients identified, only 0.1% had a concurrent spinopelvic fusion. A THA dislocation was observed in 3 of 15 patients (20.0%) and 3 of 18 THA (16.7%) within our institutional review. Within the Humana database, 8.3% of patients with THA and spinopelvic fusion went on to have a dislocation of their THA compared to 2.9% of patients with THA and no history of spinopelvic fusion (relative risk: 2.9 [1.2-7.6]). CONCLUSION: Among patients with spinopelvic fusion, the prevalence of concurrent THA is 4.6%, and among primary THA patients, the prevalence of concurrent spinopelvic fusion is 0.1%. An alarmingly high THA dislocation rate has been demonstrated among THA patients with concurrent spinopelvic fusion at our institution (20%) and within a large national database (8.3%).

Reliability Of A Surgeon-Reported Morbidity And Mortality Database: A Comparison Of Short-Term Morbidity Between The Scoliosis Research Society And National Surgical Quality Improvement Program Databases.

BACKGROUND: There exists a lack of comparison between large national healthcare databases reporting surgical morbidity and mortality. Prior authors have expressed concern that the Scoliosis Research Society (SRS) membership may have underreported complications in spinal surgery. Thus, the purpose of the present study was to compare the incidence of morbidity between the SRS and National Surgical Quality Improvement Program (NSQIP) databases. METHODS: We reviewed patients enrolled between 2012 and 2013, with a total of 96,875 patients identified in the SRS dataset and 15,909 in the combined adult and pediatric NSQIP dataset. Patients were matched based on diagnostic category,and a univariate analysis was used to compare reported complication rates in the categories of perioperative infection, neurologic injury, and mortality. The SRS database only requires detailed demographic data reporting on patients that have had a complication event. We compared the demographics and comorbidities of this subgroup, and used this as a surrogate to assess the potential magnitude of confounders. RESULTS: Small differences existed between the SRS and NSQIP databases in terms of mortality (0.1% v. 0.2%), infection (1.2% v. 2%), and neurologic injury (0.8% v. 0.1%) (p<0.001 for each comparison). Infection rates were consistently lower across multiple diagnostic sub-categories in the SRS database, whereas neurologic injury rates were consistently lower in the NSQIP database. These differences reached statistical significance across several diagnostic subcategories, but the clinical magnitude of the differences was small. Amongst the patients with a complication, modest differences in comorbidities existed between the two cohorts. CONCLUSION: Overall, the incidence of short-term morbidity and mortality was similar between the two databases. There were modest differences in comorbidities, which may explain the small differences observed in morbidity. Concerns regarding possible under-reporting of morbidity and mortality data by the SRS membership seem largely unfounded. This study may be useful for future investigators using the NSQIP and SRS datasets.

Pediatric Spine Trauma in the United States--Analysis of the HCUP Kid'S Inpatient Database (KID) 1997-2009.

BACKGROUND: Few references are available describing the epidemiology of pediatric spine injuries. The purpose of this study is to examine the prevalence, risk factors and trends during the period from 1997 to 2009 of pediatric spine injuries in the United States using a large national database. METHODS: Data was obtained from the Kid's Inpatient Database (KID) developed by the Healthcare Cost and Utilization Project (HCUP), for the years 1997-2009. This data includes >3 million discharges from 44 states and 4121 hospitals on children younger than 20 years. Weighted variables are provided which allow for the calculation of national prevalence rates. The Nationwide Emergency Department Sample (NEDS), HCUP. net, and National Highway Traffic Safety Administration (NHTSA) data were used for verification and comparison. RESULTS: A prevalence of 107.96 pmp (per million population) spine injuries in children and adolescents was found in 2009, which is increased from the 77.07 pmp observed in 1997. The group 15 to 19 years old had the highest prevalence of all age groups in (345.44 pmp). Neurological injury was present in 14.6% of the cases, for a prevalence of 15.82 pmp. The majority (86.7%) of these injuries occurred in children >15 years. Motor vehicle collisions accounted for 52.9% of all spine injuries, particularly in children >15 years. Between 1997 and 2009 the hospital length of stay decreased, but hospital charges demonstrated a significant increase. CONCLUSIONS: Pediatric Spine Injuries continue to be a relevant problem, with rates exceeding those of other industrialized nations. Teenagers >15 years of age were at greatest risk, and motor vehicle collisions accounted for the most common mechanism. An increase in prevalence was observed between 1997 and 2009, and this was matched by a similar increase in hospital charges. LEVEL OF EVIDENCE: III.

Selective Thoracic Fusion of Lenke I and II Curves Affects Sagittal Profiles But Not Sagittal or Spinopelvic Alignment: A Case-Control Study.

STUDY DESIGN: Literature review and retrospective case-control study (level 3 evidence) examining 50 adolescent idiopathic scoliosis (AIS) (Lenke I or II curve) cases with 32 healthy controls of the same age. The sagittal profiles were measured preoperatively, 6 months, and 2 years after surgery and compared with those of age-matched controls at baseline. OBJECTIVE: The purpose of this study is to compare baseline sagittal profiles of AIS Lenke I and II curves with age-matched healthy controls and at 6 months and 2 years after surgery, as well as with previously published reports. SUMMARY OF BACKGROUND DATA: Sagittal alignment and profiles have gained significant attention in spinal deformity outcomes. The sagittal profile of patients with AIS has been previously reported, as well as the effects of surgical correction, with inconsistent results and no clear references to nonscoliotic controls. METHODS: Baseline sagittal profiles of 50 patients presenting with Lenke I or II AIS curves treated with selective thoracic fusion were compared with 32 age-matched controls without spinal pathology. These values were also measured at 6 months and 2 years postoperatively to examine effects of selective thoracic fusion over time. Sagittal parameters examined include pelvic incidence, pelvic tilt, C7 plumb line (sagittal vertical alignment), thoracic kyphosis, and lumbar lordosis. A literature review was performed comparing previously published data. Data are presented as mean (95% confidence interval). P value of less than 0.05 was considered significant. RESULTS: Interobserver reliability (Cohen κ= 0.49-0.95). All demographic and preoperative sagittal alignment parameters were comparable between controls and patients with AIS prior to surgery. After selective thoracic fusion, thoracic kyphosis decreased significantly from baseline (25.4º [21.6-29.2] vs. 15.3º [12.8-17.8]; P < 0.001) at 6 months and at 2 years (10.3º [7.5-13.1]; P < 0.001). The lumbar lordosis significantly decreased at 6 months from baseline (54.5º [28.6-80.5] vs. 61.8º (33.4-90.1); P < 0.001) and at 2 years (55.4º [29.0-81.9]; P < 0.001). Sagittal vertical alignment, pelvic tilt, and pelvic incidence were comparable between controls and patients with AIS at baseline and did not change with surgery. CONCLUSIONS: Adolescents with Lenke I or II curves have comparable sagittal profiles with those of healthy controls of the same age. This suggests that Lenke I and II curves may not be hypokyphotic as previously thought. After selective thoracic fusion, patients with AIS have a significantly decreased thoracic kyphosis, which is accompanied by reciprocal changes in the noninstrumented lumbar curve. Sagittal vertical alignment and pelvic tilt are not significantly affected. These results agree with previous reports, which suggest that constructs with pedicle screws have a higher impact on sagittal curves but do not affect sagittal or spinopelvic alignment. The long-term effects of abnormal sagittal profiles need further clarification. LEVEL OF EVIDENCE: 3.

The Impact of Renal Impairment on Short-term Morbidity Risk Following Lumbar Spine Surgeries.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To determine a cutoff below which worsening renal function is associated with increased risk of morbidity and to determine the types and magnitude of morbidity associated with renal impairment. SUMMARY OF BACKGROUND DATA: Renal impairment is associated with an increased risk of morbidity after lumbar spine surgery. However, the degree to which increasing levels of renal dysfunction are associated with morbidity has not been well defined. METHODS: A large, multicenter, clinical registry was queried for all adult patients undergoing lumbar spine surgery in 2012, and 13,576 cases were identified. An estimated glomerular filtration rate (eGFR) was calculated for each patient. Propensity scores were used to match patients on the basis of preoperative comorbidities and the procedure-type performed. The incidence of 30-day morbidity was then compared between patients with no or mild renal impairment (eGFR ≥60 mL/min/1.73 m) and those with moderate or severe disease (eGFR <60 mL/min/1.73 m). Separately, the morbidity risk associated with eGFR was analyzed as a continuous variable. RESULTS: The risk of morbidity increased with worsening eGFR in an inverse-logarithmic fashion (R = 0.84), and the magnitude of risk increased substantially for eGFR below 60 mL/min/1.73 m (odds ratio of ≥1.8). There was a 26% relative increase in morbidity for patients with moderate to severe renal impairment, as compared with the propensity score-matched cohort of patients with no or mild disease (5% absolute increase, 24% vs. 19%, P = 0.004). Wound complications (3% vs. 2.1%), reoperation rates (4.6% vs. 3.3%), and need for blood transfusions (16.3% vs. 12.8%) trended higher in patients with moderate or severe disease, but only the need for blood transfusion reached significance. Patients with preoperative moderate or serve renal impairment were 10 times more likely to develop acute renal failure postoperatively (0.6% vs. 0.06%, P = 0.01). CONCLUSION: Thirty-day morbidity risk after lumbar spine surgery is strongly associated with renal impairment. These data may be useful for preoperative patient counseling, and surgeons should consider the relative magnitude of risks and benefits before operating on a patient with severe renal disease, particularly in elective cases. LEVEL OF EVIDENCE: 3.

Thirty-Day Morbidity After Single-Level Anterior Cervical Discectomy and Fusion: Identification of Risk Factors and Emphasis on the Safety of Outpatient Procedures.

BACKGROUND: Risk factors for complication after single-level anterior cervical discectomy and fusion remain poorly defined. The purpose of this study was to identify the incidence and risk factors for complication from a large, prospectively collected database, with a separate emphasis on the safety of outpatient procedures. METHODS: The American College of Surgeons National Surgical Quality Improvement Program prospectively collects thirty-day morbidity and mortality data from more than 480 hospitals around the United States. We retrospectively queried this database to identify cases of single-level elective anterior cervical discectomy and fusion. Univariate and multivariate analyses were used to identify risk factors for complication, and a propensity score model was used to create matched inpatient and outpatient cohorts. RESULTS: Of 2914 cases identified, 597 (20.5%) received outpatient treatment and 2317 (79.5%) received inpatient treatment. The overall incidence of any systemic morbidity was 3.2%. There were five mortalities (0.2%), four in the inpatient cohort and one in the outpatient cohort. Patient age over sixty-five years, body mass index of >30 kg/m2, American Society of Anesthesiologists class of 3 or 4, current dialysis, current corticosteroid use, recent sepsis, and operative times longer than 120 minutes were each independent risk factors for complication in the multivariate analysis. After propensity score matching to control for comorbidities, there were no significant differences in complication rates between inpatients and outpatients, and outpatient treatment was not a risk factor for complication in the multivariate analysis. CONCLUSIONS: Single-level elective anterior cervical discectomy and fusion had low complication rates, with no additional risk seen with outpatient as compared with inpatient procedures. It seems reasonable to consider inpatient admission for any patient with the risk factors identified here, particularly difficult airways. This information may be useful to surgeons performing informed consents for medical optimization and for selecting patients most appropriate for outpatient treatment. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Increasing hospital charges for adolescent idiopathic scoliosis in the United States.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the trends and causes for increases in hospital charges in adolescent idiopathic scoliosis (AIS) fusions. SUMMARY OF BACKGROUND DATA: Trends in utilization rates, surgical procedure types, and hospital charges for AIS fusions have not been well investigated. METHODS: We used International Classification of Diseases, Ninth Revision, billing codes to identify 29,594 AIS fusion cases from the National Inpatient Service (NIS) database between 2001 and 2011. Data were trended over time, and contrasted against other common procedures. To identify specific drivers of charges, we queried our own hospital's billing system, and averaged charges from 40 cases (10 cases for each of 4 yr studied). Dollar amounts were adjusted for inflation to 2011 dollars. RESULTS: Utilization rates for AIS fusions have remained constant, whereas utilization of adult spinal fusions increased by 64% (P = 0.0004). Utilization of anterior thoracic fusions decreased by 80% (P < 0.0001). Mean hospital charges for AIS spinal fusions increased from $72,780 in 2001 to $155,278 in 2011 (113% increase), averaging 11.3% annually (P < 0.0001), with charges for adult spinal procedures increasing at a similar rate (13.4% annually, P < 0.0001). Charges for the other nonspine conditions increased to a lesser degree (range of 4.5%-6% annually, P < 0.001 for each). At our institution, spinal implant charges increased 27.6% annually, whereas surgeon charges decreased 0.5% annually, and all other charges increased only 5.2% annually. Over time, our surgeon used greater numbers of pedicle screws, and greater numbers of implants per surgery and per level fused (P < 0.05 for each). Implant charges were 28% of the total hospital bill in 2003, rising to 53% in 2012. CONCLUSION: Although utilization rates for AIS fusions have remained constant over time, hospital charges have increased substantively, and there has been a shift toward performing posterior only surgical procedures. This corresponds to the widespread adoption of pedicle screw-based constructs. Spinal implants may be the primary driver of increased charges. Strategies directed toward implant cost savings may thus have the largest impact. LEVEL OF EVIDENCE: 4.

Causes and risk factors for 30-day unplanned readmissions after lumbar spine surgery.

STUDY DESIGN: Retrospective review of a prospective cohort. OBJECTIVE: To determine the incidence, causes, and risk factors for 30-day unplanned readmissions after lumbar spine surgery. SUMMARY OF BACKGROUND DATA: The rising costs associated with lumbar spinal surgery have received national attention. Recently, the government has chosen to target 30-day readmissions as a quality measure. Few studies have specifically analyzed the incidence, causes, and risk factors for readmission in a multicenter patient cohort. METHODS: A large, multicenter clinical registry was queried for all patients undergoing lumbar spine surgery in 2012. Current Procedural Terminology codes were used to select patients undergoing lumbar discectomy, laminectomy, anterior and posterior fusions, and multilevel deformity surgery. Thirty-day readmissions rates and causes were identified and analyzed. Univariate and multivariate logistic regression analyses were used to identify patient characteristics, comorbidities, and operative variables predictive of readmission. RESULTS: Overall, 695 of 15,668 patients undergoing lumbar spine surgery had unplanned 30-day hospital readmissions (4.4%). When separated by procedure type, readmissions were lowest after discectomy, 3.3%, and highest after deformity surgery, 9.0% (P < 0.001). The top causes for readmission were wound-related (38.6%), pain-related (22.4%), thromboembolic (9.4%), and systemic infections (8.0%). Predictors of readmission included advanced patient age more than 80 years (P = 0.03), African American race (P = 0.03), recent weight loss (P = 0.04), chronic obstructive pulmonary disorder (P < 0.01), history of cancer (P = 0.04), creatinine more than 1.2 (P < 0.01), elevated ASA class (P = 0.01), operative time more than 4 hours (P = 0.01), and prolonged hospital length of stay more than 4 days (P < 0.01). CONCLUSION: Thirty-day unplanned readmission rates increased with procedure invasiveness. Both medical and surgical reasons contributed to readmission, many unavoidable. Surgeons should explore optimization measures for those at risk of early, unplanned readmission. LEVEL OF EVIDENCE: 3.

Differences in short-term complications between spinal and general anesthesia for primary total knee arthroplasty.

BACKGROUND: Spinal anesthesia has been associated with lower postoperative rates of deep-vein thrombosis, a shorter operative time, and less blood loss when compared with general anesthesia. The purpose of the present study was to identify differences in thirty-day perioperative morbidity and mortality between anesthesia choices among patients undergoing total knee arthroplasty. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database was searched to identify patients who underwent primary total knee arthroplasty between 2005 and 2010. Complications that occurred within thirty days after the procedure in patients who had been managed with either general or spinal anesthesia were identified. Patient characteristics, thirty-day complication rates, and mortality were compared. Multivariate logistic regression identified predictors of thirty-day morbidity, and stratified propensity scores were used to adjust for selection bias. RESULTS: The database search identified 14,052 cases of primary total knee arthroplasty; 6030 (42.9%) were performed with the patient under spinal anesthesia and 8022 (57.1%) were performed with the patient under general anesthesia. The spinal anesthesia group had a lower unadjusted frequency of superficial wound infections (0.68% versus 0.92%; p = 0.0003), blood transfusions (5.02% versus 6.07%; p = 0.0086), and overall complications (10.72% versus 12.34%; p = 0.0032). The length of surgery (ninety-six versus 100 minutes; p < 0.0001) and the length of hospital stay (3.45 versus 3.77 days; p < 0.0001) were shorter in the spinal anesthesia group. After adjustment for potential confounders, the overall likelihood of complications was significantly higher in association with general anesthesia (odds ratio, 1.129; 95% confidence interval, 1.004 to 1.269). Patients with the highest number of preoperative comorbidities, as defined by propensity score-matched quintiles, demonstrated a significant difference between the groups with regard to the short-term complication rate (11.63% versus 15.28%; p = 0.0152). Age, female sex, black race, elevated creatinine, American Society of Anesthesiologists class, operative time, and anesthetic choice were all independent risk factors of short-term complication after total knee arthroplasty. CONCLUSIONS: Patients undergoing total knee arthroplasty who were managed with general anesthesia had a small but significant increase in the risk of complications as compared with patients who were managed with spinal anesthesia; the difference was greatest for patients with multiple comorbidities. Surgeons who perform knee arthroplasty may consider spinal anesthesia for patients with comorbidities.